tests: make test-convert-bzr.t more stable The test would occasionally fail because datesort don't have sub-second granularity and thus can't sort commits made in the same second. The test is made more stable by adding 1 second of sleep to make sure the bzr commits are done with different timestamps.

casecollision: add tests Add more tests to exercise the case collion detection code

dirstate: add dir/file collision test Add a test exercising collisions in add between files and directories of the same name.

dirstate: factor common update code into _addpath Factor update code common to all callers of _addpath into _addpath. By centralizing the update code here, it provides one place to put updates to new data structures - in a future patch. It also removes a few lines of duplicate code.

test-subrepo-relative-path: partially adapt for Windows

tests: make rm of usercache in test-largefiles.t more robust Recursive removal of a different path could be fatal - better avoid recursive rm completely.

merge with stable