Extract SuperMemberData from JavaScriptBackend

tests/compiler/dart2js/inference/inference_test_helper.dart

Index: tests/compiler/dart2js/inference/inference_test_helper.dart
diff --git a/tests/compiler/dart2js/inference/inference_test_helper.dart b/tests/compiler/dart2js/inference/inference_test_helper.dart
index fa380f672867a246546cbc4edf9ccf97eec93440..4b6636e7249c2c2c2ddb0fb38746d83748ba5d91 100644
--- a/tests/compiler/dart2js/inference/inference_test_helper.dart
+++ b/tests/compiler/dart2js/inference/inference_test_helper.dart
@@ -48,8 +48,7 @@ checkCode(String annotatedCode, CheckMemberFunction checkMember,
         computeSpannable(compiler.elementEnvironment, mainUri, id),
         'expected:${expected},actual:null');
   });
-  Expect.isTrue(expectedMap.isEmpty,
-      "Ids not found: $expectedMap.");
+  Expect.isTrue(expectedMap.isEmpty, "Ids not found: $expectedMap.");
 }
 
 void checkMemberAstTypeMasks(