This reverts commit 68a7736b.

Reason for revert: Broke Bazel and gcc builds
https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux64%20-%20bazel%20-%20builder/2237/overview
https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux%20gcc%20-%20builder/2103/overview

Original change's description:
> [snapshot] Rename embedded*.S files to .asm
>
> We want to use llvm-ml to assemble files on Windows, but it only
> recognizes .asm files as input files. See
> https://chromium-review.googlesource.com/c/v8/v8/+/3668287.
>
> Change-Id: I34ff6d2693a34653c8e22a7c2d093853505cd455
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3672420
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
> Reviewed-by: Andreas Haas <ahaas@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#80782}

Change-Id: I92f4435aca26da16555734b95b9aabe3271af15c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3673428
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Shu-yu Guo <syg@chromium.org>
Owners-Override: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80784}