windows: wrap `os.getcwd()` in `os.path.realpath()` on py3 I noticed various `test-check-*` failures that were printing absolute paths when repo relative paths were expected. This was due to the drive letter in `repo.root` being uppercased as it is run through `os.path.realpath()`, and then the simple string comparison against the (lowercased) `_cwd` member of dirstate in `dirstate.getcwd()` causing an absolute path to be returned, instead of the expected `b''`. That in turn causes `scmutil.getuipathfn()` to wrongly use `repo.pathto()` with an absolute cwd path. . Differential Revision: https://phab.mercurial-scm.org/D9806