This CL fixes a memory leak where we would not properly pop all
Promises from the Isolate-wide Promise stack. This can happen under
the following conditions:
  - `await`ing a Promise in an async function
  - Debugger is active
  - AsyncEventDelegate is not set.

In the case above, the promise of the surrounding async function is
pushed onto the global Promise stack, but not poped before the
await. This CL fixes that.

R=bmeurer@chromium.org

Fixed: chromium:1225905
Change-Id: If03f6bfda48b8cb14bc6a68815fd702632edc68d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3268464Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77790}