The AsyncCompileJob should be decoupled from tiering, hence the
top-tier-finished callback should not be delivered via the
AsyncCompileJob. Instead, store it directly on the CompilationState.

R=ahaas@chromium.org

Bug: v8:8050, v8:7921, chromium:912031
Change-Id: Iebd64655667a8078c34caea4edeb6cf5f40833fd
Reviewed-on: https://chromium-review.googlesource.com/c/1371604Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58165}