dart2js: run dartfmt on tests

tests/compiler/dart2js_extra/lookup_map/live_entry_through_mirrors_used_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Subset of dead_entry_through_mirrors_test that is not affected by
 // tree-shaking. This subset can be run in the VM.
 library live_entry_through_mirrors_used_test;
 
 import 'package:lookup_map/lookup_map.dart';
 import 'package:expect/expect.dart';
 
 @MirrorsUsed(targets: const [A])
 import 'dart:mirrors';
 
-class A{}
-class B{}
+class A {}
+
+class B {}
+
 const map = const LookupMap(const [
-    A, "the-text-for-A",
-    B, "the-text-for-B",
+  A,
+  "the-text-for-A",
+  B,
+  "the-text-for-B",
 ]);
 
 main() {
   // `A` is included by @MirrorsUsed, so its entry is retained too.
-  LibraryMirror lib = currentMirrorSystem().findLibrary(
-      #live_entry_through_mirrors_used_test);
+  LibraryMirror lib =
+      currentMirrorSystem().findLibrary(#live_entry_through_mirrors_used_test);
   ClassMirror aClass = lib.declarations[#A];
   Expect.equals(map[aClass.reflectedType], "the-text-for-A");
 }