dart2js: run dartfmt on tests

tests/compiler/dart2js_extra/if_null_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.
 
 import "package:expect/expect.dart";
 
-@NoInline() @AssumeDynamic()
+@NoInline()
+@AssumeDynamic()
 confuse(x) => x;
 
 main(args) {
   var x = new A();
   var y;
 
   // Checks that inference doesn't incorrectly treat this as a normal
   // assignment (where only B is a possible value after the assignment).
   var c = x ??= new B();
   var z = x;
   Expect.equals('a', x.m());
   Expect.equals('a', z.m());
   Expect.equals('a', c.m());
   if (confuse(true)) y = x;
   Expect.equals('a', y.m());
 
   // Similar test, within fields.
   new C();
   new D();
 }
 
-class A { m() => 'a'; }
-class B { m() => 'b'; }
+class A {
+  m() => 'a';
+}
+
+class B {
+  m() => 'b';
+}
 
 class C {
   var y;
   C() {
     y = new A();
     var c = y ??= new B();
     Expect.equals('a', y.m());
     Expect.equals('a', c.m());
   }
 }
 
 class D {
   var y;
   D() {
     this.y = new A();
     var c = this.y ??= new B();
     Expect.equals('a', y.m());
     Expect.equals('a', c.m());
   }
 }