status: don't list files as both removed and deleted
When calculating status involving the working copy and a revision
other than the parent of the working copy, the files that are not in
the working context manifest ('mf2' in the basectx._buildstatus())
will be reported as removed (note that deleted files _are_ in the
working context manifest). However, if the file is reported as deleted
in the dirstate, it will get that status too (as shown by failing
tests).
Fix by removing deleted files from the 'removed' list after the main
loop in _buildstatus().