This is a reland of commit 3ce690ee

Changed for the reland:
- Remove the currently-unused BytecodeArray member to avoid MSAN
  failures.
- s/return/continue/ in optimizing-compile-dispatcher.

Original change's description:
> [osr] Basic support for concurrent OSR
>
> 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/+/3548820
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Jakob Linke <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#79685}

Bug: v8:12161
Change-Id: I48b100e5980c909ec5e79d190aaea730c83e9386
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3565720Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Jakob Linke <jgruber@chromium.org>
Auto-Submit: Jakob Linke <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79746}