Allow calls to not specify a safepoint. When we look up the safepoint
for such a location, we return a default safepoint which just has the
stack slots and no deopt info or pushed registers. This is different to
the TF safepoint elision, which tries to find the _next_ safepoint for a
PC. This allows us to let most calls not specify a safepoint at all, at
the cost of not being able to deduplicate safepoints anymore.

Bug: v8:7700
Change-Id: Ia119f56f40b5af426e0daa521801e6386b28ddb0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3770106Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81958}