[turbofan][arm64] Replace TruncateInt64ToInt32(BitcastTaggedToWordForTagAndSmiBits(Load(x))) with Load(x)

This allows arm64 to produce an extending load from ChangeInt32ToInt64(Load(x)) more frequently.
Reduces embedded code size by 0.66% for arm64.

This change gives 0.3% for Speedometer on an A55 machine.

Change-Id: Ie27a134cea3dfc8a26b87553f27ca01bf9f00f1a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3803227Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Commit-Queue: George Wort <george.wort@arm.com>
Cr-Commit-Position: refs/heads/main@{#82258}