Remove toplevel inference restriction hints, and restore as much

pkg/analyzer/test/generated/hint_code_test.dart

Index: pkg/analyzer/test/generated/hint_code_test.dart
diff --git a/pkg/analyzer/test/generated/hint_code_test.dart b/pkg/analyzer/test/generated/hint_code_test.dart
index 7f1f4fc6be3e0dbf4f903c4195de7effc197bea4..0456fede20cc137467816826238bf4319292df5f 100644
--- a/pkg/analyzer/test/generated/hint_code_test.dart
+++ b/pkg/analyzer/test/generated/hint_code_test.dart
@@ -2587,20 +2587,6 @@ main() {
     verify([source]);
   }
 
-  test_strongMode_topLevelInstanceGetter() async {
-    resetWith(options: new AnalysisOptionsImpl()..strongMode = true);
-    Source source = addSource(r'''
-class A {
-  int get g => 0;
-}
-var a = new A();
-var b = a.g;
-''');
-    await computeAnalysisResult(source);
-    assertErrors(source, [StrongModeCode.TOP_LEVEL_INSTANCE_GETTER]);
-    verify([source]);
-  }
-
   test_typeCheck_type_is_Null() async {
     Source source = addSource(r'''
 m(i) {