- Remove flag --block-concurrent-recompilation and its implementation,
  including %UnblockConcurrentCompilation.
- Rewrite tests that used it in terms of the primitives introduced in
  my previous CL:
  https://chromium-review.googlesource.com/c/v8/v8/+/3071400/
- Remove "sync"/"no sync" arguments from %GetOptimizationStatus,
  assertOptimized, etc. These are now always "no sync": they don't
  do any magic.
- Remove "if %IsConcurrentRecompilationSupported then quit" from some
  tests in favor of --concurrent-recompilation in their Flags line.

Bug: v8:12041, v8:7790
Change-Id: I966aae4fec85e6f9e7aeed2ba2c12e9198a3991f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3077149Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76298}

This is a reland of e70cbb83

Moved the ConsString comparison logic out-of-line, both to make gcc
happy, and to reduce the size of the fast-path in IsEqualToImpl.

Original change's description:
> [string] Fix non-SeqStrings in IsEqualTo
>
> Bug: chromium:1193903
> Change-Id: I80704dd3cba5754779432356b20bd3ea99630291
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2794426
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Auto-Submit: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73746}

Bug: chromium:1193903
Change-Id: Iae6f078853438427e86d3ac68bcfed0712a85bf7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2797288
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73763}

This reverts commit e70cbb83.

Reason for revert: Breaks compile on gcc.
https://ci.chromium.org/p/v8/builders/ci/V8%20Linux%20gcc/11148

Original change's description:
> [string] Fix non-SeqStrings in IsEqualTo
>
> Bug: chromium:1193903
> Change-Id: I80704dd3cba5754779432356b20bd3ea99630291
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2794426
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Auto-Submit: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73746}

Bug: chromium:1193903
Change-Id: If700cdc7cf8b50a9430d17489485769cb524efd5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2797539
Auto-Submit: Bill Budge <bbudge@chromium.org>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#73749}

Bug: chromium:1193903
Change-Id: I80704dd3cba5754779432356b20bd3ea99630291
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2794426
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73746}