Fix unparsing of variable definitions.

tests/compiler/dart2js/unparser_test.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.
 
 #import('dart:uri');
 #import('parser_helper.dart');
 #import("../../../lib/compiler/compiler.dart");
 #import("../../../lib/compiler/implementation/tree/tree.dart");
 
 testUnparse(String statement) {
@@ skipping 124 matching lines @@
 }
 
 testClassWithSynthesizedConstructor() {
   testDart2Dart('main(){new A();}class A{}');
 }
 
 testClassWithMethod() {
   testDart2Dart('main(){var a=new A(); a.foo();}class A{void foo(){}}');
 }
 
+testVariableDefinitions() {
+  testDart2Dart('main(){final var x, y; final String s;}');
+  testDart2Dart('foo(f, g){}main(){foo(1, 2);}');
+  testDart2Dart('foo(f(arg)){}main(){foo(main);}');
+}
+
 main() {
   testGenericTypes();
   testForLoop();
   testEmptyList();
   testClosure();
   testIndexedOperatorDecl();
   testNativeMethods();
   testPrefixIncrements();
   testConstModifier();
   testSimpleFileUnparse();
   testSimpleObjectInstantiation();
   testSimpleTopLevelClass();
   testClassWithSynthesizedConstructor();
   testClassWithMethod();
+  testVariableDefinitions();
   testTopLevelField();
 }