numOpsGet not update for successful gets in EventuallyPersistentEngine::getInner()

This is a production bug rather than test issue. We are not updating numOpsGet anymore for the gets made in this test (gets made via EventuallyPersistentEngine::getInner()). If the WorkLoadMonitor runs after the sets during the test and before all of the sets then it's possible to change the workload to write_heavy and not change it back. This is a regression introduced by this change https://review.couchbase.org/c/kv_engine/+/139024/7/engines/ep/src/ep_engine.cc#b2417.

Original manifestation:

http://cv.jenkins.couchbase.com/job/kv_engine.linux-CE/job/master/16363/

Failure of an engine_testapp test:

Running [0103/0159]: test multiple vb compactions with workload...Exceeded maximum wait time of 60000000us waiting for stat 'ep_workload_pattern' to be read_heavy (last value:write_heavy) - aborting.