RuntimeCallTimerScope can now be called with the optional flag
kThreadSpecific, which chooses the appropriate RuntimeCounterId given
whether the RuntimeCallStats object is for the main isolate thread or a
worker thread.

While this doesn't change any existing timers over to use this flag it
does add checks that in the default case that any thread-specific
counters are the correct one given the thread status.

Bug: v8:10006
Change-Id: Idb545714284bcd2e2fdca991918ddf976dcbdf70
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1928863
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65125}