revsetbenchmark: add entry for ::rev::
Revsets of the form ::rev:: were identified as the source behind the
regressions in issue 4201. Ensure we have explicit coverage of that
revset.
all()draft()::tipdraft() and ::tip0::tiproots(0::tip)author(lmoscovicz)author(mpm)author(lmoscovicz) or author(mpm)tip:0max(tip:0)min(0:tip)0::min(0::)::p1(p1(tip))::