Intermittent failure in ep_engine test 'test dcp cursor dropping' (ASan)

Following intermittent failure seen during CV run:

00:12:22.616 Running [0033/0085]: test dcp cursor dropping (couchstore).../home/couchbase/jenkins/workspace/kv_engine-addresssanitizer-master/kv_engine/engines/ep/tests/ep_testsuite_dcp.cc:838 Test failed: `Unexpected DCP operation: 88' (false)

00:12:22.616 (11365 ms) DIED

Note: opcode '88' is DCP_DELETION, which /shouldn't/ be created during this test .

here was a similar issue previously - MB-17564 - which attempted to solve this by clearing the various DCP data when opening a connection. Maybe we have a similar issue again?

Logs: http://cv.jenkins.couchbase.com/job/kv_engine-addresssanitizer-master/1438/consoleFull#836439947c5751633-7aa5-473a-91e8-426e0afa5a7b