Preserve Mock process across test classes

This makes the runs quicker. Java process instantiation isn't cheap

Change-Id: If2a1b8d18b1983830c4d2dd9fc17d5b5b40fd9ba
Reviewed-on: http://review.couchbase.org/28046
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>