repo.status: also compare flags for files in the lookup list.
We might be able to do something smarter about this in dirstate.status
for files in normallookup state, but that would require some extra
care to keep backwards compatibility.
# should print nothing
# should fail
abort: path 'b/x' is inside repo 'b'
abort: path 'b/x' is inside repo 'b'
# should fail
abort: path 'b/x' is inside repo 'b'
# should arguably print nothing
# should fail
abort: path 'b/a' is inside repo 'b'