call the compiler can clobber the tested register. Moving this tricky
part into a noninlinable lambda allows to reduce pressure from the
register allocator and thereby avoid such clobbering.

Subtle: between the first inline assembly and the IteratePointers()
Change-Id: Ibeca8fa2f4fd54d07c2f585a4e876504a6a991b7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2859843
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74280}