This CL reverts two diagnosing CLs that introduced same-thread CHECKS,
recovering all introduced performance regressions.

We will try to add less performance-sensitive checks again in a follow
up.

This reverts commit 0c2bbfd5.
This reverts commit 6643c059.

Bug: chromium:1253650, chromium:1243257, chromium:1274201
Change-Id: I96c41c39c4f58b062574fa11c4a2d76ad030bcf7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3315437
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Auto-Submit: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78245}