TimeTicks cannot convert to other timeunits, only TimeDelta can
do that. Chrome's version of TimeBase introduced a `since_origin`
helper that essentially converts a TimeTicks object in to a
TimeDelta with the corresponding duration.

This CL ports that helper to V8 and cleans up a couple of places
where we used `timestamp - 0` to convert a TimeTicks object to
a TimeDelta.

Change-Id: I540ced876ac3e727dfdedf7b838a272cc40d6954
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1993282
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65820}