Strong mode cleaning of many dart2js tests.

tests/compiler/dart2js/call_site_simple_type_inferer_test.dart

Index: tests/compiler/dart2js/call_site_simple_type_inferer_test.dart
diff --git a/tests/compiler/dart2js/call_site_simple_type_inferer_test.dart b/tests/compiler/dart2js/call_site_simple_type_inferer_test.dart
index 44ea2ba36dbf1d3142e5f7b7f8bcadc2f4856579..525f1a47e58cba74302542e47888c8be7fdeca39 100644
--- a/tests/compiler/dart2js/call_site_simple_type_inferer_test.dart
+++ b/tests/compiler/dart2js/call_site_simple_type_inferer_test.dart
@@ -14,7 +14,7 @@ void compileAndFind(String code, String className, String memberName,
   Uri uri = new Uri(scheme: 'source');
   var compiler = compilerFor(code, uri, disableInlining: disableInlining);
   asyncTest(() => compiler.run(uri).then((_) {
-        var cls = findElement(compiler, className);
+        dynamic cls = findElement(compiler, className);

[Emily Fortuna, 2017/06/15 18:33:10]

ClassElement?

[ahe, 2017/06/16 07:26:46]

Done.

         var member = cls.lookupLocalMember(memberName);
         return check(compiler, member);
       }));