LU-17788 ptlrpc: restore watchdog revival message

LU-17788 ptlrpc: restore watchdog revival message

Restore the "Service thread pid NNN completed after SSS.mmm
seconds.  This likely indicates the system was overloaded"
message that was lost during ptlrpc watchdog restructuring.

Do not rate limit this message, so that it is possible to see
when all threads are restored, even if their corresponding
"Service thread pid NNN was inactive" message was throttled.

Update recovery-small test_10a to check for these messages,
so that they are not removed again in the future.

Lustre-change: https://review.whamcloud.com/54942
Lustre-commit: 20c09eff4d397e7158aa4408e0cb50b102cc61c0

Test-Parameters: testlist=recovery-small env=ONLY=10a
Fixes: fc9de679a4 ("LU-9859 libcfs: add watchdog for ptlrpc service threads.")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I0c7e96fb7f73ca5562a6f5ad780a79ffc83ebbe5
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/55095
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>