Unskip Impeller iOS scenario tests (#55012)

The iOS golden scenario tests are supposed to run on Skia and Impeller, but are actually running on Skia twice.  

#### Issue 1: script-side

Regression from #46329.
Currently, the tests log "Running simulator tests with Impeller" but then you see that it's not:
```
Running simulator tests with Impeller
...
2024-09-06 13:38:07.692810-0700 Scenarios[73857:470266] [IMPORTANT:flutter/shell/common/shell.cc(456)] [Action Required] The application opted out of Impeller by either using the --no-enable-impeller flag or FLTEnableImpeller=false plist flag. This option is going to go away in an upcoming Flutter release. Remove the explicit opt-out. If you need to opt-out, report a bug describing the issue.
```
https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket/8737514337106072353/+/u/test:_Scenario_App_Integration_Tests/stdout

`INFOPLIST_FILE="Scenarios/Info_Impeller.plist"` isn't passed into the xcodebuild any more.  I confirmed #46329 caused this by inserting a comment in the middle of the `xcodebuild` command, which caused the last argument after the comment to not be passed in.

#### Issue 2: test-side

Regression from #45093.
[The logic deciding whether to use Skia or Impeller goldens is incorrect](https://github.com/flutter/engine/blob/397987aedeb4ed41ec945fcbe9d347e579513bf4/testing/scenario_app/ios/Scenarios/ScenariosUITests/GoldenTestManager.m#L84-L90) since `FLTEnableImpeller` is set in the app Info.plist, not the UI test, so the bundle should be "dev.flutter.Scenarios". That means even if the script was passing in the right Info.plist, the tests would fail since they would have compared the Skia screenshots.

#### This PR

1. Once #55016 merges (edit: done), these tests will no longer be running with the software renderer.  Remove all the test skips so they all run on Impeller.
2. Add the missing Impeller golden screenshots.
3. Update the default Info.plist to use Impeller, so if another script mishap happens, it will default to testing Impeller twice, and not Skia.  Add a Skia Info.plist variant instead.
4. Update the test logic to check the right bundle ID Info.plist to decide whether to compare against the Skia or Impeller screenshots.  Prefer Impeller so if another test-side mishap happens, it will also default to testing Impeller and not Skia.  It will only use the Skia goldens if the bool is set in the Info.plist, and that bool is NO (not just if it's missing).
5. All this made the now-default Impeller tests pass, but when passing in `INFOPLIST_FILE="Scenarios/Info_Skia.plist"` the app wasn't launching, with the error:

> Scenarios encountered an error (Failed to install or launch the test runner. (Underlying Error: Simulator device returned an error for the requested operation. Failed to create promise. (Underlying Error: Failed to create app extension placeholder for /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Scenarios-aypjgouuxctxctfazxalyegcximf/Build/Products/Debug-iphonesimulator/Scenarios.app/PlugIns/ScenariosShare.appex. Failed to create promise. (Underlying Error: Failed to set placeholder attributes dev.flutter.Scenarios.ScenariosShare. Failed to create promise. (Underlying Error: extensionDictionary must be set in placeholder attributes for an app extension placeholder. Invalid placeholder attributes.)))))

This is identical to the error in #53717. I finally realized it was because the ScenariosShare app extension requires specific extension keys in its plist, which weren't present in the app Info.plist at `Scenarios/Info_Skia.plist`.  So I changed the `INFOPLIST_FILE` path to `$(TARGET_NAME)/Info_Skia.plist` so it would resolve to target-specific copies like `Scenarios/ScenariosShare/Info_Skia.plist`.  That meant I had to add a few more copies where they didn't exist in the target path.

Dependent on #55016 landing.
Fixes flutter/flutter#131888

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

Author: jmagman

testing/scenario_app/bin/run_ios_tests.dart

@@ -138,6 +138,11 @@ Future<void> _run(
       osVersion: osVersion,
       deviceName: deviceName,
       iosEngineVariant: iosEngineVariant,
+      xcodeBuildExtraArgs: [
+        // Plist with `FTEEnableImpeller=NO`; all projects in the workspace require this file.
+        // For example, `FlutterAppExtensionTestHost` has a dummy file under the below directory.
+        r'INFOPLIST_FILE="$(TARGET_NAME)/Info_Skia.plist"',
+      ],
     );
     cleanup.add(process.kill);
 
@@ -161,10 +166,6 @@ Future<void> _run(
       osVersion: osVersion,
       deviceName: deviceName,
       iosEngineVariant: iosEngineVariant,
-      xcodeBuildExtraArgs: [
-        ..._skipTestsForImpeller,
-        _infoPlistFPathForImpeller(engine),
-      ],
     );
     cleanup.add(process.kill);
 
@@ -349,64 +350,6 @@ Future<io.Process> _runTests({
   );
 }
 
-/// -skip-testing {$name} args required to pass the Impeller tests.
-///
-/// - Skip testFontRenderingWhenSuppliedWithBogusFont: https://github.com/flutter/flutter/issues/113250
-/// - Skip golden tests that use software rendering: https://github.com/flutter/flutter/issues/131888
-final _skipTestsForImpeller = [
-  'ScenariosUITests/MultiplePlatformViewsBackgroundForegroundTest/testPlatformView',
-  'ScenariosUITests/MultiplePlatformViewsTest/testPlatformView',
-  'ScenariosUITests/NonFullScreenFlutterViewPlatformViewUITests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipPathTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipPathMultipleClipsTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipPathWithTransformTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipPathWithTransformMultipleClipsTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipRectAfterMovedTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipRectAfterMovedMultipleClipsTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipRectTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipRectMultipleClipsTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipRectWithTransformTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipRectWithTransformMultipleClipsTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipRRectTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipRRectMultipleClipsTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipRRectWithTransformTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationClipRRectWithTransformMultipleClipsTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationLargeClipRRectTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationLargeClipRRectMultipleClipsTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationLargeClipRRectWithTransformTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationLargeClipRRectWithTransformMultipleClipsTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationOpacityTests/testPlatformView',
-  'ScenariosUITests/PlatformViewMutationTransformTests/testPlatformView',
-  'ScenariosUITests/PlatformViewRotation/testPlatformView',
-  'ScenariosUITests/PlatformViewUITests/testPlatformView',
-  'ScenariosUITests/PlatformViewWithNegativeOtherBackDropFilterTests/testPlatformView',
-  'ScenariosUITests/PlatformViewWithOtherBackdropFilterTests/testPlatformView',
-  'ScenariosUITests/TwoPlatformViewClipPathTests/testPlatformView',
-  'ScenariosUITests/TwoPlatformViewClipPathMultipleClipsTests/testPlatformView',
-  'ScenariosUITests/TwoPlatformViewClipRectTests/testPlatformView',
-  'ScenariosUITests/TwoPlatformViewClipRectMultipleClipsTests/testPlatformView',
-  'ScenariosUITests/TwoPlatformViewClipRRectTests/testPlatformView',
-  'ScenariosUITests/TwoPlatformViewClipRRectMultipleClipsTests/testPlatformView',
-  'ScenariosUITests/TwoPlatformViewsWithOtherBackDropFilterTests/testPlatformView',
-  'ScenariosUITests/UnobstructedPlatformViewTests/testMultiplePlatformViewsWithOverlays',
-].map((name) => '-skip-testing:$name').toList();
-
-/// Plist with `FTEEnableImpeller=YES`; all projects in the workspace require this file.
-///
-/// For example, `FlutterAppExtensionTestHost` has a dummy file under the below directory.
-String _infoPlistFPathForImpeller(Engine engine) {
-  final infoPath = path.join(
-    engine.flutterDir.path,
-    'testing',
-    'scenario_app',
-    'ios',
-    'Scenarios',
-    'Scenarios',
-    'Info_Impeller.plist',
-  );
-  return 'INFOPLIST_FILE=$infoPath';
-}
-
 @useResult
 String _zipAndStoreFailedTestResults({
   required String iosEngineVariant,

testing/scenario_app/ios/FlutterAppExtensionTestHost/Scenarios/Info_Impeller.plist renamed to testing/scenario_app/ios/FlutterAppExtensionTestHost/FlutterAppExtensionTestHost/Info_Skia.plist

@@ -1,11 +1,11 @@
-<!--Dummy plist file to make the impeller version of scenario test happy-->
+<!--Dummy plist file to make the Skia version of scenario test happy-->
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
 	<!--This flag does not do anything, it only makes the xcodebuild command happy-->
 	<key>FLTEnableImpeller</key>
-	<true/>
+	<false/>
 	<key>UIApplicationSceneManifest</key>
 	<dict>
 		<key>UIApplicationSupportsMultipleScenes</key>