PollDeviceBackend [kqueue]: Fixes related to PIKE_FD_FS_EVENT.
Updating the FS_EVENT notification flags should now work better.
Testsuite [kqueue]: Fixed typo in chmod test.
Octal numbers need to be prefixed with 0...
Also increases the test paranoia by forcing the umask, and testing
by removing read for other (instead of adding rwx for all).
Fixes chmod failing for "Unknown reason" on FreeBSD.
Testsuite [kqueue]: Fixed another typo.
Testsuite [kqueue]: Fixed typo.
Testsuite [kqueue]: Improved diagnostics.
Log the test that is in progress, and the tests that fail.
Also don't abort the kqueue test program after the first failed test.