Scripts aren't callable functions. Even though internally they were for a
while, they aren't anymore. We shouldn't return them to users as if they were.
We already remove strict-mode functions from CallSites, so we now do the same
for internal functions that are created for scripts.

Bug: v8:10508
Change-Id: I270c714524439fba9ad90dd29826bed4811ba2b4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2193716
Auto-Submit: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67709}