match: avoid rust fast path if the matcher was tampered with
Otherwise the fast path does not respect the modifications made
by the extension (concretely largefiles, but other extensions can
start using that too)
#require cargo test-repo
$ . "$TESTDIR/helpers-testrepo.sh"
$ cd "$TESTDIR"/../rust
Check if Cargo.lock is up-to-date. Will fail with a 101 error code if not.
$ cargo check --locked --all --quiet
However most CIs will run `cargo build` or similar before running the tests, so we need to check if it was modified
$ testrepohg diff Cargo.lock