This is the follow-up CL to
https://chromium-review.googlesource.com/#/c/v8/v8/+/931122.

Now that HeapConstants can be loaded through the builtins constants
table, the extra CallStub and CallRuntime has become unnecessary.

Bug: v8:6666
Change-Id: I02bb7805ac37bed6fe27fdd0689ac22ad7de034b
Reviewed-on: https://chromium-review.googlesource.com/931123
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51512}