LU-15403 tests: fix some false alarm

LU-15403 tests: fix some false alarm

Current test implementation have a two bugs.
1) client mgc llogs processing is async to mount,
so we can start a lock check before all locks processed.
it caused a false alarm. Same story with several client mounts.

2) Server locks counting is unsafe, as it include an other server
locks. so any servers reconnect may cause a false alarm.

Let's fix it.

HPe-bug-id: LUS-8326
Test-Parameters: trivial testlist=sanityn
Signed-off-by: Alexey Lyashkov <alexey.lyashkov@hpe.com>
Change-Id: I59d6e5deb79ca9f040385231738b8698a3309e8e
Reviewed-on: https://review.whamcloud.com/45958
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andrew Perepechko <andrew.perepechko@hpe.com>
Reviewed-by: Sergey Cheremencev <sergey.cheremencev@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>