CBQE-1220 Add warmup test with reboot operation

Change-Id: I33e5a70fb23d0f75cb11eddd1bcca636b4911e8c
Reviewed-on: http://review.couchbase.org/26370
Reviewed-by: Chisheng Hong <chisheng@couchbase.com>
Tested-by: Chisheng Hong <chisheng@couchbase.com>