test: fix test-fs-watch-system-limit

On some systems the default inotify limits might be too high for the
test to actually fail. Detect and skip the test in such environments.

PR-URL: https://github.com/nodejs/node/pull/23986


Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>