Avoid generating is$Object, and fix a typo in a condition.

lib/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.
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
 class ClosureInvocationElement extends FunctionElement {
   ClosureInvocationElement(SourceString name,
@@ skipping 654 matching lines @@
     classElement.forEachMember(includeBackendMembers: true,
                                f: (ClassElement enclosing, Element member) {
       assert(invariant(classElement, member.isDeclaration));
       if (member.isInstanceMember()) {
         addInstanceMember(member, defineInstanceMember);
       }
     });
 
     generateIsTestsOn(classElement, (Element other) {
       String code;
+      if (other.isObject(compiler)) return;
       if (nativeEmitter.requiresNativeIsCheck(other)) {
         code = 'function() { return true; }';
       } else {
         code = 'true';
       }
       CodeBuffer typeTestBuffer = new CodeBuffer();
       typeTestBuffer.add(code);
       defineInstanceMember(namer.operatorIs(other), typeTestBuffer);
     });
 
@@ skipping 749 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].
 """;