global: use pycompat.xrange()
On Python 3, our module importer automatically rewrites xrange()
to pycompat.xrange().
We want to move away from the custom importer on Python 3.
This commit converts all instances of xrange() to use
pycompat.xrange().
Differential Revision: https://phab.mercurial-scm.org/D4032
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}