status: when extracting arguments from `opts`, use the same default values

Sometimes other code, such as commit when using `commands.commit.post-status`,
calls `commands.status()` without going through the normal dispatch mechanism
that would typically fill in the args to be something besides None. As a
"defense in depth" mechanism for a bug where Mercurial would crash if both
`commands.commit.post-status` and `experimental.directaccess` were enabled,
let's sanitize these values to be identical to the values they would have when
the user invoked this method from the commandline.

Differential Revision: https://phab.mercurial-scm.org/D11884

mercurial/commands.py

@@ -6873,9 +6873,9 b' def status(ui, repo, *pats, **opts):'
 
     cmdutil.check_at_most_one_arg(opts, 'rev', 'change')
     opts = pycompat.byteskwargs(opts)
-    revs = opts.get(b'rev')
-    change = opts.get(b'change')
-    terse = opts.get(b'terse')
+    revs = opts.get(b'rev', [])
+    change = opts.get(b'change', b'')
+    terse = opts.get(b'terse', _NOTTERSE)
     if terse is _NOTTERSE:
         if revs:
             terse = b''