pullbundle: attempt to save stablerange cache after each computation
Since we do not serve the full repository, we use more stablerange starting from
a random point. These are probably not loaded yet and should be cached.
This is best effort caching, if we can't save them we won't.
. $TESTDIR/testlib/pythonpath.sh
cat >> $HGRCPATH << EOF
[extensions]
docgraph=
EOF