[regexp] Turn last match info into a simple FixedArray

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 5c77aa4e95a8d2d22a112838e376cc1ee45039ba..6fba6956015a6569cfdf896a1ae793be79eb3729 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1699,6 +1699,7 @@ void Genesis::InitializeGlobal(Handle<JSGlobalObject> global_object,
     shared->set_instance_class_name(isolate->heap()->RegExp_string());
     shared->DontAdaptArguments();
     shared->set_length(2);
+
     {
       // RegExp.prototype setup.
 
@@ -1875,6 +1876,13 @@ void Genesis::InitializeGlobal(Handle<JSGlobalObject> global_object,
       function->shared()->set_native(true);
       isolate->native_context()->set(Context::REGEXP_INTERNAL_MATCH, *function);
     }
+
+    // Create the last match info. One for external use, and one for internal
+    // use when we don't want to modify the externally visible match info.
+    isolate->native_context()->set_regexp_last_match_info(
+        *factory->NewRegExpMatchInfo());
+    isolate->native_context()->set_regexp_internal_match_info(
+        *factory->NewRegExpMatchInfo());
   }
 
   {  // -- E r r o r