rust-dirstatemap: add missing @propertycache While investigating a regression on `hg update` performance introduced by the Rust `dirstatemap`, two missing `@propertycache` were identified when comparing against the Python implementation. This adds back the first one, that has no observable impact on behavior. The second one (`nonnormalset`) is going to be more involved, as the caching has to be done from the Rust side of things. Differential Revision: https://phab.mercurial-scm.org/D8047

--- a/mercurial/dirstate.py	Thu Jan 30 19:16:12 2020 +0100
+++ b/mercurial/dirstate.py	Wed Jan 29 11:11:18 2020 +0100
@@ -1849,7 +1849,7 @@
             nonnorm, otherparents = self._rustmap.nonnormalentries()
             return nonnorm
 
-        @property
+        @propertycache
         def otherparentset(self):
             nonnorm, otherparents = self._rustmap.nonnormalentries()
             return otherparents