Instead of looking up the specific maps in every native context, just
check against the instance type.

Bug: v8:11256
Change-Id: Ib50d599c014c95b03ba3260014dfcbd9ec82982c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2593337Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71802}