Added %_NewConsString intrinsic.

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 6ea782760fa71e47aabb2420b00e233361605a09..1cdce60874abfe6671852f1c725202a7f27efc61 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -538,10 +538,30 @@ MaybeHandle<String> Factory::NewConsString(Handle<String> left,
             NewRawTwoByteString(length).ToHandleChecked(), left, right);
   }
 
-  Handle<Map> map = (is_one_byte || is_one_byte_data_in_two_byte_string)
-                        ? cons_one_byte_string_map()
-                        : cons_string_map();
-  Handle<ConsString> result =  New<ConsString>(map, NEW_SPACE);
+  return (is_one_byte || is_one_byte_data_in_two_byte_string)
+             ? NewOneByteConsString(length, left, right)
+             : NewTwoByteConsString(length, left, right);
+}
+
+
+MaybeHandle<String> Factory::NewOneByteConsString(int length,
+                                                  Handle<String> left,
+                                                  Handle<String> right) {
+  return NewRawConsString(cons_one_byte_string_map(), length, left, right);
+}
+
+
+MaybeHandle<String> Factory::NewTwoByteConsString(int length,
+                                                  Handle<String> left,
+                                                  Handle<String> right) {
+  return NewRawConsString(cons_string_map(), length, left, right);
+}
+
+
+MaybeHandle<String> Factory::NewRawConsString(Handle<Map> map, int length,
+                                              Handle<String> left,
+                                              Handle<String> right) {
+  Handle<ConsString> result = New<ConsString>(map, NEW_SPACE);
 
   DisallowHeapAllocation no_gc;
   WriteBarrierMode mode = result->GetWriteBarrierMode(no_gc);