Increase the number of file descriptors available

The 'listenlist_test', 'notify_test', and 'query_test' tests failed when the descriptor limit was 256 on MacOS 11.6 with 8 cpus. On the test platform the limit needed to be increased to ~400. Increase the limit to at least 1024 to give some head room.

(cherry picked from commit 877f52b7)

Closes #2900 (closed)