CBD-1386:  add ubuntu-1204-x64 TOY builder

Change-Id: I4d6a928471e0db40ae61f72fdcbdcc223d0563bb
Reviewed-on: http://review.couchbase.org/37897
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>