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

src/regexp/jsregexp-inl.h

Index: src/regexp/jsregexp-inl.h
diff --git a/src/regexp/jsregexp-inl.h b/src/regexp/jsregexp-inl.h
index 3eb7c3c1704b998b6bebe5b06bbbed65d156ffc3..ca7a9fe9918630719570c68a86ac4ec9629c794c 100644
--- a/src/regexp/jsregexp-inl.h
+++ b/src/regexp/jsregexp-inl.h
@@ -47,7 +47,10 @@ int32_t* RegExpImpl::GlobalCache::FetchNext() {
                                              register_array_size_);
     } else {
       int last_start_index = last_match[0];
-      if (last_start_index == last_end_index) last_end_index++;
+      if (last_start_index == last_end_index) {
+        // Zero-length match. Advance by one code point.
+        last_end_index = AdvanceZeroLength(last_end_index);
+      }
       if (last_end_index > subject_->length()) {
         num_matches_ = 0;  // Signal failed match.
         return NULL;