Following up on https://crrev.com/c/3383775 we are now able to further
simplify the implementation of `await` and its instrumentation (for both
debugger and promise hooks), which aligns the implementation more
closely with the spec text and removes a whole bunch of unnecessary
code.

This also moves the `await` instrumentation into runtime-debug.cc along
with the other instrumentation methods for async functions.

Bug: chromium:1280519, chromium:1277451, chromium:1246867
Change-Id: I3fb543c76229091b502f3188da962784977158ab
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3386597
Auto-Submit: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78610}