This reverts commit 656c74218f.
Reason for revert: crbug.com/v8/13715
Original change's description:
> [liftoff] Combine "InitMerge" with the actual merge
>
> "InitMerge" did compute the state at the merge point, and a following
> "MergeStackWith" or "MergeFullStackWith" would then generate the code to
> merge the current state into the computed state.
> As every "InitMerge" is followed by an actual merge, we can combine the
> two and save one iteration over the two states.
>
> The only change in generated code is that we initialize the merge state
> after a one-armed if from the if-state instead of the else-state. This
> could potentially make the if-branch slightly cheaper and the
> else-branch slightly slower, but will not negatively impact overall code
> size.
>
> This CL should save roughly 2% of Liftoff compilation time.
>
> R=dlehmann@chromium.org
>
> Bug: v8:13565, v8:13673
> Change-Id: Id323a15e7fd765727f46830509fbaf7f5498c229
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4203380
> Reviewed-by: Daniel Lehmann <dlehmann@chromium.org>
> Commit-Queue: Clemens Backes <clemensb@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#85616}
Bug: v8:13565, v8:13673, v8:13715
Change-Id: I5342833aaa9c8665a514b3702eaf783d512dfa5f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4222633
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#85659}
702fdc02a2