A custom deoptimization continuation point erroneously cast a parameter
to a number. Tests added.

BUG: v8:7672
Change-Id: I59848aacdedc1de9fd7d83d55045618f37d39fb0
Reviewed-on: https://chromium-review.googlesource.com/c/1485974Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59841}