Allow extending `RecordingBugReporter`.

PiperOrigin-RevId: 372579909
diff --git a/src/test/java/com/google/devtools/build/lib/buildtool/util/BuildIntegrationTestCase.java b/src/test/java/com/google/devtools/build/lib/buildtool/util/BuildIntegrationTestCase.java
index dea2b7e..5173510 100644
--- a/src/test/java/com/google/devtools/build/lib/buildtool/util/BuildIntegrationTestCase.java
+++ b/src/test/java/com/google/devtools/build/lib/buildtool/util/BuildIntegrationTestCase.java
@@ -859,7 +859,7 @@
   }
 
   /** {@link BugReporter} that stores bug reports for later inspection. */
-  protected static final class RecordingBugReporter implements BugReporter {
+  protected static class RecordingBugReporter implements BugReporter {
     @GuardedBy("this")
     private final List<Throwable> exceptions = new ArrayList<>();