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

tests/compiler/dart2js/gvn_test.dart

Index: tests/compiler/dart2js/gvn_test.dart
diff --git a/tests/compiler/dart2js/gvn_test.dart b/tests/compiler/dart2js/gvn_test.dart
index c63b2c6708e929475d4ffd82220b4b2b29e691d7..72716ca2324c404db5eb6f44716e47605599cb9c 100644
--- a/tests/compiler/dart2js/gvn_test.dart
+++ b/tests/compiler/dart2js/gvn_test.dart
@@ -15,7 +15,7 @@ void foo(bar) {
 
 main() {
   String generated = compile(TEST_ONE, 'foo');
-  RegExp regexp = const RegExp(r"1 \+ bar");
+  RegExp regexp = const RegExp(r"1 \+ [a-z]+");
   Iterator matches = regexp.allMatches(generated).iterator();
   Expect.isTrue(matches.hasNext());
   matches.next();