- Add Turboshaft to the wasm pipeline (behind a flag).
- Add a few operators.
- Implement SimplifyLoopsPhase, which ensures each loop has at most
  two inputs.
- Remove the unneeded effect argument from
  {FlagContinuation::FromTrap}.

Bug: v8:12783
Change-Id: I03a3f8cf3af40fc75bf57cfbad973b754b13dd8c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3899126
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83365}