More strong mode fixes for analyzer

pkg/analyzer/test/src/task/strong/strong_test_helper.dart

Index: pkg/analyzer/test/src/task/strong/strong_test_helper.dart
diff --git a/pkg/analyzer/test/src/task/strong/strong_test_helper.dart b/pkg/analyzer/test/src/task/strong/strong_test_helper.dart
index f17517d5b752328aff1e00b7fb0956d83d22b28c..6e5b83b40ac2be624f5c16d236fe3635768c5cb5 100644
--- a/pkg/analyzer/test/src/task/strong/strong_test_helper.dart
+++ b/pkg/analyzer/test/src/task/strong/strong_test_helper.dart
@@ -63,8 +63,9 @@ CompilationUnit check() {
   var uriResolver = new _TestUriResolver(files);
   // Enable task model strong mode
   var context = AnalysisEngine.instance.createAnalysisContext();
-  context.analysisOptions.strongMode = true;
-  (context.analysisOptions as AnalysisOptionsImpl).strongModeHints = true;
+  AnalysisOptionsImpl options = context.analysisOptions as AnalysisOptionsImpl;
+  options.strongMode = true;
+  options.strongModeHints = true;
   context.sourceFactory =
       new SourceFactory([new DartUriResolver(new MockSdk()), uriResolver]);