tests: stabilize test-extdiff.t on Windows...
tests: stabilize test-extdiff.t on Windows
This goes with 765a9c299c44. I'm not sure if we care about the missing file
being spelled `nul`, so I removed it from the glob to be explicit about it. The
line needed to be special cased anyway because of the quoting on Windows.
Differential Revision:
https://phab.mercurial-scm.org/D7572