branchmap: close cache file properly Follows up 2a4bfbb52111.

branchmap: strip '\n' read from cache file as before Follows up 2a4bfbb52111.

rebase: do not pass in user option to rollback in-memory merge conflict Nothing passed before e9e742bd0501.

rebase: add test for in-memory merge conflicts

rebase: call _dorebase() properly This fixes a regression from e9e742bd0501 where we failed to pass all necessary arguments to _dorebase(). Differential Revision: https://phab.mercurial-scm.org/D4302

context: make sure file is not deleted while checking path conflicts If a file is deleted and a directory of same name is created in the same commit, IMM thinks of that as a file conflict, however the file is deleted and hence the directory can be created. The test change demonstrate the fix. Differential Revision: https://phab.mercurial-scm.org/D4300

tests: demonstrate that IMM needs to be smarter with path conflicts When we try to rebase a commit which deletes an existing file and make a directory of the same name, rebase with IMM aborts. It should work fine just like the without IMM case. Differential Revision: https://phab.mercurial-scm.org/D4299