This fixes a long-standing TODO to disallow importing receivers that
have "toString" or "valueOf" patched. Calling those methods could have
observable side effects, so allowing that would require bigger
refactorings to ensure that we only call each such function exactly once
per import, and in the right order.
Since this use case is rare, we just forbid importing such receivers.

R=jkummerow@chromium.org

Bug: chromium:1248677
Change-Id: I99bbd7db950ec3c7ac9cc1f59e8c476688e7d7b6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3190475Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77149}