[regexp] Turn last match info into a simple FixedArray

src/factory.h

Index: src/factory.h
diff --git a/src/factory.h b/src/factory.h
index 0fad42d5c514903d6d89b13396817d1b461fe974..b23adde732903a8d388fbe04b0b116e5bc4ada38 100644
--- a/src/factory.h
+++ b/src/factory.h
@@ -726,6 +726,8 @@ class Factory final {
                                         int number_of_properties,
                                         bool* is_result_from_cache);
 
+  V8_EXPORT_PRIVATE Handle<RegExpMatchInfo> NewRegExpMatchInfo();
+
   // Creates a new FixedArray that holds the data associated with the
   // atom regexp and stores it in the regexp.
   void SetRegExpAtomData(Handle<JSRegExp> regexp,