Generate Tbz/Tbnz instead of (tst;bcc),
and Cbz/Cbnz instead of (cmp;bcc), where possible.

This improves Speedometer2 by 0.22% on a Neoverse-N1 machine.

Change-Id: Ie86bae7189a7a4bd4975f946e7413225c9023316
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3833816
Commit-Queue: Martyn Capewell <martyn.capewell@arm.com>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82657}