Higher consumer rss in timer performance tests

Build 6.5.0-4282

We observed improvement in timers performance numbers due to commit

We also observed consumer rss for timers is more than doubled.

e.g. for test "Timers executed/sec, 1 bucket x 100M x 1KB, 4KV + 1Eventing node, single timer, no context-NOOP" attached is cbmonitor comparison for consumer rss.

cbmonitor link - http://cbmonitor.sc.couchbase.com/reports/html/?snapshot=themis_650-4218_process_timer_events_9203&snapshot=themis_650-4282_process_timer_events_1c49

Job- http://perf.jenkins.couchbase.com/job/themis/3884/