ScriptContextTableRef::lookup() isn't called.

BUG=v8:7790

Change-Id: I8a89de2dff7b7e4ef7b37f54a0bd0fcae27d1a1d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2196183
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67746}