Resolve a hang in ZFS during vnode reclaimation

This is caused by a deadlock between zil_commit() and zfs_zget()

Add a way for zfs_zget() to break out of the retry loop in the common case

PR: 229614
Reported by: grembo, Andreas Sommer, many others
Tested by: Andreas Sommer, Vicki Pfau
Reviewed by: avg (no objection)
Approved by: re (gjb)
MFC after: 2 months
Sponsored by: Klara Systems
Differential Revision: https://reviews.freebsd.org/D17460