This reverts commit 9f902b74.

Reason for revert: Reverting due to various fuzzing issues (numfuzz issues listed in original CL comments, ochang fuzzer in https://bugs.chromium.org/p/chromium/issues/detail?id=1299418)

Original change's description:
> [turbofan] Making OSR concurrent
>
> ... to reduce compilation overhead on the main thread for OSR
>
> Bug: v8:12161
> Change-Id: I54ca5fa6201405daf92dac9cf51d5de4b46577b3
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3369361
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Fanchen Kong <fanchen.kong@intel.com>
> Cr-Commit-Position: refs/heads/main@{#79188}

Bug: v8:12161
Change-Id: Id6f6086517cd77fb1aa60b20fd03528b8e2ca686
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3477104
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Owners-Override: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79194}