match: don't util.normpath() cwd

The problem here is that `util.normpath()` calls `util.pconvert()`, which
switches to Unix style separators.  That results in two test failures like this
since 5685ce2ea3bf:

    --- c:/Users/Matt/hg/tests/test-globalopts.t
    +++ c:/Users/Matt/hg/tests/test-globalopts.t.err
    @@ -89,7 +89,7 @@
       [255]
       $ hg -R b ann a/a
       abort: a/a not under root '$TESTTMP/b'
    -  (consider using '--cwd b')
    +  (consider using '--cwd ..\$TESTTMP\b')
       [255]
       $ hg log
       abort: no repository found in '$TESTTMP' (.hg not found)!

    ERROR: test-globalopts.t output changed

Martin originally had `os.path.normpath()` (which *would* work here too), but
changed it during review.  He didn't remember why he thought any form is needed
here.  Most uses simply pass '' or `repo.getcwd()`, so these should generally be
in local format anyway.  It seems better if `cwd` and `root` use consistent
styles here.

Differential Revision: https://phab.mercurial-scm.org/D7725

mercurial/match.py

@@ -232,7 +232,7 b' def match('
     False
     """
     assert os.path.isabs(root)
-    cwd = util.normpath(os.path.join(root, cwd))
+    cwd = os.path.join(root, util.localpath(cwd))
     normalize = _donormalize
     if icasefs:
         dirstate = ctx.repo().dirstate