Fix underflow when the break type list is empty, and do not try to
reuse the first value to generate the wanted type.

Bug: chromium:1084452
Change-Id: Ia9855a267730bb9f427518c27157f449475fb6ba
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2208858Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67895}