LU-6602 update: split update llog record

If the update llog record size exceeds the limit (llog
chunk size), which usually happens when creating striped
directory with large stripe count , then it will be split
into mulitple records, and these update records will have
the same batchid.

During recovery, these records will be combined and
constructed into the updates of one operation, then
do update replay.

Allow multiples stripes in a single MDT, so it can verify
creating large stripes in small scale test environment.

Add sanity 300j/300k and replay-single 116 to verify it.

Signed-off-by: wang di <di.wang@intel.com>
Change-Id: I86ca2594fe62d5b921e794de4cd88981d91f7677
Reviewed-on: http://review.whamcloud.com/15162
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>