Fix unit tests.

sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart

 // Copyright (c) 2012, 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.
 
 part of js_backend;
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
@@ skipping 872 matching lines @@
         buffer.addCharCode(GETTER_CODE + flag);
       } else if (needsSetter) {
         buffer.addCharCode(SETTER_CODE + flag);
       }
       buffer.add('"');
     });
     if (!isFirstField) {
       // There was at least one field.
       buffer.add(']');
       if (emitEndingComma) {
-        buffer.add(', ');
+        buffer.add(',');
       }
     }
   }
 
   /** Each getter/setter must be prefixed with a ",\n ". */
   void emitClassGettersSetters(ClassElement classElement,
                                CodeBuffer buffer,
                                bool emitLeadingComma) {
     visitClassFields(classElement, (Element member,
                                     String name,
@@ skipping 852 matching lines @@
 const String HOOKS_API_USAGE = """
 // Generated by dart2js, the Dart to JavaScript compiler.
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;