test(ecstore): cover the io_uring per-disk probe cache hit (rustfs/backlog#1101)
Follow-up to #4635. The per-disk negative probe cache was implemented but had
no dedicated test. Add uring_probe_cache_skips_known_unsupported_disk: a root
recorded in URING_UNSUPPORTED_DISKS makes try_new return None without a fresh
probe. Completes the #1101 acceptance ("cache hit does not re-probe").
Co-authored-by: heihutu <[email protected]>