dart2js: run dartfmt on tests

tests/compiler/dart2js_native/native_field_invocation6_test.dart

 // Copyright (c) 2014, 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 "dart:_js_helper";
 import "package:expect/expect.dart";
 
-makeA() native;
-nativeFirst(x, y) native;
+makeA() native ;
+nativeFirst(x, y) native ;
 
 void setup() native """
 nativeFirst = function(x, y) { return x; }
 
 function A() {}
 makeA = function() { return new A; }
 """;
 
-
 @Native("A")
 class A {
   var _foo;
 
   get foo => _foo;
 
   init() {
     _foo = () => 42;
   }
 }
@@ skipping 17 matching lines @@
   var b = new B();
   var c = new C();
   var d = new D();
   a = nativeFirst(a, b);
   a = nativeFirst(a, c);
   a = nativeFirst(a, d);
   // The variable a is still an instance of class A, but dart2js can't infer
   // that anymore.
   Expect.equals(42, a.foo());
 }