Add --no-declaration-casts option to 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 43b66d9a51fe105a6b3e9ad812a9aabc7bc10068..c4c461e97240fc5edf097ea18ac4f2e7b98396ab 100644
--- a/pkg/analyzer/test/src/task/strong/strong_test_helper.dart
+++ b/pkg/analyzer/test/src/task/strong/strong_test_helper.dart
@@ -270,7 +270,8 @@ class AbstractStrongTest {
   ///
   /// Returns the main resolved library. This can be used for further checks.
   Future<CompilationUnit> check(
-      {bool implicitCasts: true,
+      {bool declarationCasts: true,
+      bool implicitCasts: true,
       bool implicitDynamic: true,
       List<String> nonnullableTypes:
           AnalysisOptionsImpl.NONNULLABLE_TYPES}) async {
@@ -283,6 +284,7 @@ class AbstractStrongTest {
     AnalysisOptionsImpl analysisOptions = new AnalysisOptionsImpl();
     analysisOptions.strongMode = true;
     analysisOptions.strongModeHints = true;
+    analysisOptions.declarationCasts = declarationCasts;
     analysisOptions.implicitCasts = implicitCasts;
     analysisOptions.implicitDynamic = implicitDynamic;
     analysisOptions.nonnullableTypes = nonnullableTypes;