The fast_call_count getter in d8 was not properly initialised as
throwing when called as a constructor. As a result, it was possible
to pass a new object as its `this` and then attempt to "unwrap" it,
resulting in reading OOB in the new object. This CL also strenghtens
slow_call_count and reset_counts and adds a regression test.

Bug: chromium:1241464
Change-Id: I9b6e9a4e38a974dc111a53b911c73514c30de9df
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3110369Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76426}