This CL introduces a dedicated API to retrieve the current (w.r.t. the
JS stack) script name or sourceURL. Currently, API clients will
collect multiple stack traces in increasing sizes to accomplish the
same goal. The new method walks the JS stack in the same way as the
stack trace collection mechanic but doesn't create/allocate stack info
or callsite objects along the way.

R=bmeurer@chromium.org, yangguo@chromium.org

Doc: https://bit.ly/v8-current-script-name
Bug: chromium:1286677
Change-Id: Id53e4f04bf17349d34f3d581bc712b1f4aa055db
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3382818Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78645}