Instead of a hack in the {AsyncCompileJob}, handle empty modules by
just calling the callbacks for "baseline finished" and "top tier
finished" immediately, at the point where compilation would be started
usually.

R=mstarzinger@chromium.org

Bug: v8:8916
Change-Id: Id7b32fe2508e5a8902c60865f7f7d675a7a02610
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1564054
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60785}