terse: pconvert() entries added to the temporary terse dict for Windows

Recent additional testing revealed this problem on Windows:

  --- tests/test-status.t.err
  +++ tests/test-status.t.err
  @@ -109,7 +109,7 @@

   tweaking defaults works
     $ hg status --cwd a --config ui.tweakdefaults=yes
  -  ? .
  +  ? ../a/
     ? ../b/
     ? ../in_root
     $ HGPLAIN=1 hg status --cwd a --config ui.tweakdefaults=yes
  @@ -120,7 +120,7 @@
     ? b/in_b (glob)
     ? in_root
     $ HGPLAINEXCEPT=tweakdefaults hg status --cwd a --config ui.tweakdefaults=yes
  -  ? .
  +  ? ..\a\
     ? ../b/
     ? ../in_root (glob)

AFAICT, the status list (input and output here) is always in '/' format.  The
'\' printed output on Windows is because each file is run through repo.pathto()
-> dirstate.pathto() -> util.pathto().  (And that function states that the
argument uses '/' separators.)

I fixed a similar issue in 362096cfdb1f, and given the apparent need for these
strings to be in '/' format, I wonder if cmdutil.dirnode() should be rewritten
to avoid os.path.join().  But it looks like all entries added to the temporary
terse dict should use '/' now, and cmdutil.tersedir() looks like the only user.

mercurial/cmdutil.py

@@ -552,7 +552,7 b' def tersedir(statuslist, terseargs):'
     # process each sub-directory and build tersedict
     for subdir in rootobj.subdirs.values():
         for st, f in subdir.tersewalk(terseargs):
-            tersedict[st].append(f)
+            tersedict[st].append(util.pconvert(f))
 
     tersedlist = []
     for st in allst: