One more fix for making removing overlays incremental changes.

pkg/analyzer/test/src/context/context_test.dart

Index: pkg/analyzer/test/src/context/context_test.dart
diff --git a/pkg/analyzer/test/src/context/context_test.dart b/pkg/analyzer/test/src/context/context_test.dart
index cef3f3a40dca8c21bc67b548dd2ae69336731f07..7bc47ba7aebdac6ce85f8d12e3dd62d69f9f4cfe 100644
--- a/pkg/analyzer/test/src/context/context_test.dart
+++ b/pkg/analyzer/test/src/context/context_test.dart
@@ -308,6 +308,7 @@ main() {
     expect(context.getResolvedCompilationUnit2(source, source), unit);
     // remove overlay
     context.setContents(source, null);
+    context.validateCacheConsistency();
     _analyzeAll_assertFinished();
     expect(context.getResolvedCompilationUnit2(source, source), unit);
   }