Editions: Include defaults for any features in the generated pool.

This helps make the API more complete, since the FeatureSet object will always be fully resolved on any accessible features.  This specifically targets C++ plugins though, which will now have their features filled in by default.  Before, any proto files that didn't include the language-specific features would result in unresolved extensions in the generators.

PiperOrigin-RevId: 557232654

Author: mkruskal-google

src/google/protobuf/BUILD.bazel

@@ -685,7 +685,6 @@ filegroup(
         "unittest_features.proto",
         "unittest_import.proto",
         "unittest_import_public.proto",
-        "unittest_invalid_features.proto",
         "unittest_lite_imports_nonlite.proto",
         "unittest_mset.proto",
         "unittest_mset_wire_format.proto",

src/google/protobuf/compiler/command_line_interface_unittest.cc

@@ -1564,6 +1564,10 @@ TEST_F(CommandLineInterfaceTest, Plugin_RuntimeFeatures) {
                        message_encoding: LENGTH_PREFIXED
                        json_format: ALLOW
                        raw_features { field_presence: IMPLICIT }
+                       [pb.cpp] {
+                         legacy_closed_enum: false
+                         utf8_validation: VERIFY_PARSE
+                       }
       )pb"));
   EXPECT_THAT(request.source_file_descriptors(0)
                   .message_type(0)
@@ -1577,6 +1581,10 @@ TEST_F(CommandLineInterfaceTest, Plugin_RuntimeFeatures) {
                                message_encoding: LENGTH_PREFIXED
                                json_format: ALLOW
                                raw_features { field_presence: IMPLICIT }
+                               [pb.cpp] {
+                                 legacy_closed_enum: false
+                                 utf8_validation: VERIFY_PARSE
+                               }
               )pb"));
 }