Allow for a third compilation strategy that compiles baseline code
lazily but initiates top tier compilation immediately. The strategy aims
at reducing startup time.

Bug: v8:9003
Change-Id: Ifd2060b25386c5221a45f6038c3849afeb956e69
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1571620Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Frederik Gossen <frgossen@google.com>
Cr-Commit-Position: refs/heads/master@{#61077}