py3: use range instead of xrange in tests/test-revset2.t

xrange is not present on Python 3.

Differential Revision: https://phab.mercurial-scm.org/D2331

tests/test-revset2.t

@@ -420,7 +420,7 b' test that chained `or` operations never '
 test that repeated `-r` options never eat up stack (issue4565)
 (uses `-r 0::1` to avoid possible optimization at old-style parser)
 
-  $ hg log -T '{rev}\n' `$PYTHON -c "for i in xrange(500): print '-r 0::1 ',"`
+  $ hg log -T '{rev}\n' `$PYTHON -c "for i in range(500): print '-r 0::1 ',"`
   0
   1