Use a single SBFX instruction for Word64Sar(ChangeInt32ToInt64(x), imm)
when possible.

Using PGO, this improves Speedometer2 by 0.4% on a Cortex-A55 machine,
and 0.27% on a Neoverse-N1 machine.

Change-Id: I6fea5e473f0f0869f8f6cebd9a4e61bb2fc6e9ef
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3807586Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Rodolph Perfetta <rodolph.perfetta@arm.com>
Reviewed-by: Jakob Linke <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82277}