merge: call hg.abortmerge() directly and return early It's seem really weird to go through a lot of unrelated code before we call `hg.merge(..., abort=True)` when we can just call `hg.abortmerge()` and return early. Differential Revision: https://phab.mercurial-scm.org/D7995

merge: check that there are no conflicts after --abort Same idea as in abcc82bf0717 (clean: check that there are no conflicts after, 2020-01-24). We should reuse more code here, but that will come later. Differential Revision: https://phab.mercurial-scm.org/D7994