dart2js: run dartfmt on tests

tests/compiler/dart2js_extra/12320_test.dart

 // Copyright (c) 2013, 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.
 
 import "package:expect/expect.dart";
 
 // Regression test for Issue 12320, Issue 12363.
 
 String log = '';
 int x;
 
 void main() {
   (run)(run);
   // The little dance with passing [run] as an argument to confuse the optimizer
   // so that [run] is not inlined.  If [run] is inlined, the bug (Issue 12320)
   // eliminates the following 'Expect', making the test appear to pass!
   Expect.equals('[Foo][Foo 1][Bar][Foo][Foo 0]', log);
 }
 
 void run(f) {
-  if (f is !int) {
+  if (f is! int) {
     f(1);
   } else {
     x = f;
     callFoo();
     x = 2;
     callBar();
     callFoo();
   }
 }
 
 void callFoo() {
   log += '[Foo]';
-  switch(x) {
+  switch (x) {
     case 0:
       log += '[Foo 0]';
       break;
     case 1:
       log += '[Foo 1]';
       break;
     default:
       throw 'invalid x';
   }
 }
 
 void callBar() {
   log += '[Bar]';
   x = 0;
 }