Safepoints encode which slots in a stack frame store references when a
function is called. Safepoints for normal function calls in Liftoff were
already implemented before. With this CL, a safepoint for the runtime
call in a stack check is emitted.

R=thibaudm@chromium.org, clemensb@chromium.org

Bug: v8:7581
Change-Id: Iacb8b15559502adb7622935edb0cfa7ca03d634e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2563266
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71494}