Format all tests.

tests/isolate/issue_21398_child_isolate.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 'dart:isolate';
 import "package:expect/expect.dart";
 
 class FromChildIsolate {
   String toString() => 'from child isolate';
 }
 
 main(List<String> args, message) {
   var sendPort = message;
   try {
     sendPort.send(new FromChildIsolate());
-  } catch(error) {
+  } catch (error) {
     Expect.isTrue(error is ArgumentError);
     sendPort.send("Invalid Argument(s).");
   }
 }