This reverts commit c4301c04.

Reason for revert: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux64%20GC%20Stress%20-%20custom%20snapshot/42568/overview

Original change's description:
> [maglev] Add internalized string compare fast-path
>
> - Rename TryBuildCompareOperationBranch to TryBuildCompareOperation
> - Add CheckedInternalizedString conversion Node that checks for string
>   inputs and extracts internalised Strings from ThinStrings
> - Add BranchIfReferenceCompare Node
> - Add runtime functions to create internalised and thin Strings
> - Add deopt check to test/mjsunit/maglev/int32-branch.js
>
> Bug: v8:7700
> Change-Id: I0073c24fad9e3231c985153cd27b0b8fe6ee56f0
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3664498
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Camillo Bruni <cbruni@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#81361}

Bug: v8:7700
Change-Id: Id4e18f42a5b1f0d6909b0a017ae8e289ae8c8614
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3723520
Owners-Override: Shu-yu Guo <syg@chromium.org>
Auto-Submit: Shu-yu Guo <syg@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/main@{#81363}