Fix final declarations in dart_backend_test.

tests/compiler/dart2js/dart_backend_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 "package:expect/expect.dart";
 import 'dart:async';
 import "package:async_helper/async_helper.dart";
 import 'parser_helper.dart';
 import 'mock_compiler.dart';
 import '../../../sdk/lib/_internal/compiler/compiler.dart';
@@ skipping 161 matching lines @@
 testClassWithMethod() {
   testDart2Dart('main(){var a=new A();a.foo();}class A{void foo(){}}');
 }
 
 testExtendsImplements() {
   testDart2Dart('main(){new B<Object>();}'
       'class A<T>{}class B<T> extends A<T>{}');
 }
 
 testVariableDefinitions() {
-  testDart2Dart('main(){var x,y;final String s;}');
-  testDart2Dart('main(){final int x,y;final String s;}');
+  testDart2Dart('main(){var x,y;final String s=null;}');
+  testDart2Dart('main(){final int x=0,y=0;final String s=null;}');
   testDart2Dart('foo(f,g){}main(){foo(1,2);}');
   testDart2Dart('foo(f(arg)){}main(){foo(main);}');
   // A couple of static/finals inside a class.
   testDart2Dart('main(){A.a;A.b;}class A{static const String a="5";'
       'static const String b="4";}');
   // Class member of typedef-ed function type.
   // Maybe typedef should be included in the result too, but it
   // works fine without it.
   testDart2Dart(
     'typedef void foofunc(arg);main(){new A((arg){});}'
     'class A{A(foofunc this.handler);final foofunc handler;}');
 }
 
 testGetSet() {
   // Top-level get/set.
   testDart2Dart('set foo(arg){}get foo{return 5;}main(){foo;foo=5;}');
   // Field get/set.
   testDart2Dart('main(){var a=new A();a.foo;a.foo=5;}'
       'class A{set foo(a){}get foo{return 5;}}');
   // Typed get/set.
   testDart2Dart('String get foo{return "a";}main(){foo;}');
 }
 
 testAbstractClass() {
-  testDart2Dart('main(){A.foo;}abstract class A{final static num foo;}');
+  testDart2Dart('main(){A.foo;}abstract class A{final static num foo=0;}');
 }
 
 testConflictSendsRename() {
   // Various Send-s to current library and external library. Verify that
   // everything is renamed correctly in conflicting class names and global
   // functions.
   var librarySrc = '''
 library mylib;
 
 globalfoo() {}
@@ skipping 510 matching lines @@
   testStaticAccessIoLib();
   testLocalFunctionPlaceholder();
   testMinification();
   testClosureLocalsMinified();
   testParametersMinified();
   testDeclarationTypePlaceholders();
   testPlatformLibraryMemberNamesAreFixed();
   testConflictsWithCoreLib();
   testUnresolvedNamedConstructor();
 }