match: fix the rust-side bug in visit_children_set for rootfilesin matchers
The fix is checked by `test_pattern_matcher_visit_children_set` test,
which is what caught the bug in the first place, but also by an end-to-end
test that I made for this purpose.
Accept the new results of Cargo tests
Many of these were already annotated with "FIXME", which is a good sign.
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init repo
$ cd repo
$ echo 'base' > base
$ hg ci -Ambase
adding base
$ hg qnew -mmqbase mqbase
$ hg qsave
$ hg qrestore 2
restoring status: hg patches saved state