This CL adds basic support behind --concurrent-osr,
disabled by default.

When enabled:
1) the first OSR request starts a concurrent OSR compile job.
2) on completion, the code object is inserted into the OSR cache.
3) the next OSR request picks up the cached code (assuming the request
   came from the same JumpLoop bytecode).

We add a new osr optimization marker on the feedback vector to
track whether an OSR compile is currently in progress.

One fundamental issue remains: step 3) above is not guaranteed to
hit the same JumpLoop, and a mismatch means the OSR'd code cannot
be installed. This will be addressed in a followup by targeting
specific bytecode offsets for the install request.

This change is based on fanchen.kong@intel.com's earlier
change crrev.com/c/3369361, thank you!

Bug: v8:12161
Change-Id: Ib162906dd4b6ba056f62870aea2990f1369df235
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3548820Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Jakob Linke <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79685}