CBIDXT-140: Include snapshot marker in timestamp.

Updated test cases.

Change-Id: Ia300e1457759b9c48e3e64f481792c64754b52c0
Reviewed-on: http://review.couchbase.org/40409
Reviewed-by: John Liang <johliang00@gmail.com>
Reviewed-by: Pratap Chakravarthy <prataprc@couchbase.com>
Tested-by: Pratap Chakravarthy <prataprc@couchbase.com>