Disable the GoogleTestSecurityManager by default

and explicitly enable it for tests that rely on it.

The SecurityManager is being permanently disabled in JDK 24, see https://openjdk.org/jeps/486

PiperOrigin-RevId: 696974212
Change-Id: I425c0bb66e0c1c057129712e45b60ba481971db8

Author: cushon

src/java_tools/junitrunner/java/com/google/testing/junit/runner/junit4/JUnit4Config.java

@@ -90,7 +90,7 @@ private static boolean installSecurityManager(Properties systemProperties) {
       return false; // Don't install over the specified security manager
     }
     return Boolean.valueOf(
-        systemProperties.getProperty(SHOULD_INSTALL_SECURITY_MANAGER_PROPERTY, "true"));
+        systemProperties.getProperty(SHOULD_INSTALL_SECURITY_MANAGER_PROPERTY, "false"));
   }
 
   /**

src/java_tools/junitrunner/javatests/com/google/testing/junit/runner/junit4/JUnit4ConfigTest.java

@@ -85,7 +85,7 @@ public void testShouldInstallSecurityManager_defaultValue() {
     GoogleTestSecurityManager.uninstallIfInstalled();
 
     JUnit4Config config = createConfigWithProperties(new Properties());
-    assertThat(config.shouldInstallSecurityManager()).isTrue();
+    assertThat(config.shouldInstallSecurityManager()).isFalse();
   }
 
   @Test

src/java_tools/junitrunner/javatests/com/google/testing/junit/runner/junit4/JUnit4RunnerTest.java

@@ -444,8 +444,8 @@ private static Properties createProperties(
       String apiVersion, boolean shouldInstallSecurityManager) {
     Properties properties = new Properties();
     properties.setProperty(JUnit4Config.JUNIT_API_VERSION_PROPERTY, apiVersion);
-    if (!shouldInstallSecurityManager) {
-      properties.setProperty("java.security.manager", "whatever");
+    if (shouldInstallSecurityManager) {
+      properties.setProperty(JUnit4Config.SHOULD_INSTALL_SECURITY_MANAGER_PROPERTY, "true");
     }
     return properties;
   }