revsetbenchmark: add some simpler revset for heads and roots

This revset might leverage compiled code in the future so lets start to track
them.

contrib/base-revsets.txt

@@ -1,49 +1,52
 # Base Revsets to be used with revsetbenchmarks.py script
 #
 # The goal of this file is to gather a limited amount of revsets that allow a
 # good coverage of the internal revsets mechanisms.  Revsets included should not
 # be selected for their individual implementation, but for what they reveal of
 # the internal implementation of smartsets classes (and their interactions).
 #
 # Use and update this file when you change internal implementation of these
 # smartsets classes. Please include a comment explaining what each of your
 # addition is testing. Also check if your changes to the smartset class makes
 # some of the tests inadequate and replace them with a new one testing the same
 # behavior.
 #
 # If you want to benchmark revsets predicate itself, check 'all-revsets.txt'.
 #
 # The current content of this file is currently likely not reaching this goal
 # entirely, feel free, to audit its content and comment on each revset to
 # highlight what internal mechanisms they test.
 
 all()
 draft()
 ::tip
 draft() and ::tip
 ::tip and draft()
 0::tip
 roots(0::tip)
 author(lmoscovicz)
 author(mpm)
 author(lmoscovicz) or author(mpm)
 author(mpm) or author(lmoscovicz)
 tip:0
 0::
 # those two `roots(...)` inputs are close to what phase movement use.
 roots((tip~100::) - (tip~100::tip))
 roots((0::) - (0::tip))
 42:68 and roots(42:tip)
 ::p1(p1(tip))::
 public()
 :10000 and public()
 draft()
 :10000 and draft()
 roots((0:tip)::)
 (not public() - obsolete())
 (_intlist('20000\x0020001')) and merge()
 parents(20000)
 (20000::) - (20000)
 # The one below is used by rebase
 (children(ancestor(tip~5, tip)) and ::(tip~5))::
 heads(commonancestors(last(head(), 2)))
+heads(-10000:-1)
+roots(-10000:-1)
+only(max(head()), min(head()))