[regexp] correctly advance zero length matches for global/unicode.

src/regexp/jsregexp.h

Index: src/regexp/jsregexp.h
diff --git a/src/regexp/jsregexp.h b/src/regexp/jsregexp.h
index f4051fdf43d58e942cce6ba8ae0b340952539b7f..cd3932cb55e8f1b3c8aa81019548b24135aeebfa 100644
--- a/src/regexp/jsregexp.h
+++ b/src/regexp/jsregexp.h
@@ -121,7 +121,6 @@ class RegExpImpl {
    public:
     GlobalCache(Handle<JSRegExp> regexp,
                 Handle<String> subject,
-                bool is_global,
                 Isolate* isolate);
 
     INLINE(~GlobalCache());
@@ -137,6 +136,8 @@ class RegExpImpl {
     INLINE(bool HasException()) { return num_matches_ < 0; }
 
    private:
+    int AdvanceZeroLength(int last_index);
+
     int num_matches_;
     int max_matches_;
     int current_match_index_;