This prevents an overflow to happen in the heap snapshot generator.
Furthermore it changes the relation of progress_counter_ and
progress_total_ to always adhere to:
* progress_counter_ <= progress_total_,
* if: progress_counter_ == progress_total_, then it is done.

With this change, if progress_counter_ happens to be bigger
than progress_total_ (latter is an estimate), it will continue
to report the same progress (<100%) until it is done. Before,
it would repeatedly report 100% until it is done.

Fixed: chromium:1246860
Change-Id: Iffd3f52355632f2b35abdbb3752912ba7b8bd821
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3250310Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Kim-Anh Tran <kimanh@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77589}