dirstate: respect request to not list unknown/ignored/clean files (API)

Unknown files that are explicitly mentioned by the matcher are
returned even if the caller said unknown=False (and it seems the same
is done for ignored files). That seems pretty surprising. Let's make
the interface less surprising by respecting the caller's request.

Differential Revision: https://phab.mercurial-scm.org/D7150

mercurial/dirstate.py

@@ -1149,16 +1149,19 b' class dirstate(object):'
             )
             return (lookup, status)
 
+        def noop(f):
+            pass
+
         dcontains = dmap.__contains__
         dget = dmap.__getitem__
         ladd = lookup.append  # aka "unsure"
         madd = modified.append
         aadd = added.append
-        uadd = unknown.append
-        iadd = ignored.append
+        uadd = unknown.append if listunknown else noop
+        iadd = ignored.append if listignored else noop
         radd = removed.append
         dadd = deleted.append
-        cadd = clean.append
+        cadd = clean.append if listclean else noop
         mexact = match.exact
         dirignore = self._dirignore
         checkexec = self._checkexec