Fix JS minifier to lift var declarations within functions. Still disabled.

tests/compiler/dart2js/class_codegen_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.
 // Test that parameters keep their names in the output.
 
 #import("compiler_helper.dart");
 #import("parser_helper.dart");
 
 const String TEST_ONE = r"""
 class A { }
@@ skipping 35 matching lines @@
   var z;
 }
 
 main() {
   new B();
 }
 """;
 
 const String TEST_FIVE = r"""
 class A {
-  var x;
-  A(x) : this.x = x {}
+  var a;
+  A(a) : this.a = a {}

[ngeoffray, 2012/10/15 14:20:01]

Why this change? (and the ones in the other tests?) I believe we still want to
have a nice pretty printer that keeps variable names, and it feels easier for
the tests to use that one instead of a minifier.

 }
 
 main() {
   new A(3);
 }
 """;
 
 twoClasses() {
   String generated = compileAll(TEST_ONE);
   Expect.isTrue(generated.contains('\$.A = {"":\n [],\n "super": "Object"'));
@@ skipping 15 matching lines @@
   print(generated);
   Expect.isTrue(generated.contains(r"""
 $.B = {"":
  ["y", "z", "x"],
  "super": "A"
 }"""));
 }
 
 constructor1() {
   String generated = compileAll(TEST_FIVE);
-  Expect.isTrue(generated.contains(r"new $.A(x);"));
+  Expect.isTrue(generated.contains(r"new $.A(a);"));
 }
 
 main() {
   twoClasses();
   subClass();
   fieldTest();
   constructor1();
 }