Strong mode cleaning of many dart2js tests.

tests/compiler/dart2js/simple_inferrer_unregister_call_test.dart

Index: tests/compiler/dart2js/simple_inferrer_unregister_call_test.dart
diff --git a/tests/compiler/dart2js/simple_inferrer_unregister_call_test.dart b/tests/compiler/dart2js/simple_inferrer_unregister_call_test.dart
index 8456a95deaaa714462bd5bcdd6781f3db30829e5..9b17e80870d24e1bf3eee6b6e1648c9bc1c46978 100644
--- a/tests/compiler/dart2js/simple_inferrer_unregister_call_test.dart
+++ b/tests/compiler/dart2js/simple_inferrer_unregister_call_test.dart
@@ -35,7 +35,7 @@ void main() {
         var typesInferrer = compiler.globalInference.typesInferrerInternal;
 
         checkReturnInClass(String className, String methodName, type) {
-          var cls = findElement(compiler, className);
+          dynamic cls = findElement(compiler, className);
           var element = cls.lookupLocalMember(methodName);
           Expect.equals(type, typesInferrer.getReturnTypeOfElement(element));
         }