tests: stabilize change for handling not quoting non-empty-directory The change originated in cb1329738d64. I suspect the problem is with the combination of (re) and the '\' to '/' retry on Windows. I've no idea if py3 on Windows needs the quoting, since it can't even run `hg` with no arguments. (It's dying somewhere on the ctype declarations when win32.py is imported.)

hg: wrap the highest layer in the `hg` script possible in trace event This should help us have a better idea of what "interpreter startup costs" look like. This does omit the HGUNICODEPEDANTRY block and the LIBDIR dancing to set up sys.path, but the former is usually off and the latter is unavoidable and should be very fast. If we get worried about those cases we can consider open-coding the tracing logic here. Differential Revision: https://phab.mercurial-scm.org/D4346

localrepo: use urllocalpath() for path to create repo too It looks like this was lost in 7ce9dea3a14a (localrepo: move repo creation logic out of localrepository.__init__ (API), 2018-09-11). I don't know when it makes a difference (maybe on Windows, since urllocalpath() mentions something about drive letters). Differential Revision: https://phab.mercurial-scm.org/D4550

localrepo: move check for existing repo into createrepository() For symmetry with the check for existence of a repo in localrepository.__init__, we should check for the non-existence in createrepository(). We could alternatively move both checks into instance(). Differential Revision: https://phab.mercurial-scm.org/D4549