rust-dirstatemap: add missing @propertycache...
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
