In mksnapshot, we only need to ensure we generate counter code in
(embedded) builtins, if needed. The counter function does not need to do
anything useful as long as it returns unique pointers for each counter,
and we don't need to dump counters.

Tbr: petermarshall@chromium.org
Change-Id: I94a53ef5193b89365948d0395e1908e6d3c6e396
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1549159Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60694}