Multiple initial build test regressed

Build: 7.2.0-5312 but not seen with 7.2.0-5311

Change log 

http://changelog.build.couchbase.com/?product=couchbase-server&fromVersion=7.2.0&fromBuild=5298&toVersion=7.2.0&toBuild=5312&f_analytics-dcp-client=off&f_asterixdb=off&f_cbas-core=off&f_cbgt=off&f_eventing=off&f_eventing-ee=off&f_indexing=on&f_kv_engine=off&f_libcouchbase=off&f_query=off&f_testrunner=off

Looks like we disabled OSO off , that is the root cause of the regression

Test :

 Initial index (min), 1 bucket x 500M, single 2i index, Initial build only, 50% Resident, PLASMA

Run: http://perf.jenkins.couchbase.com/job/secondary-plasma-dgm/6532/console 

logs: 

https://s3-us-west-2.amazonaws.com/perf-artifacts/jenkins-secondary-plasma-dgm-6532/172.23.97.10.zip

cbmonitor with 7.2.0-5312 vs 5311

http://cbmonitor.sc.couchbase.com/reports/html/?snapshot=nyx_720-5311_build_secondaryindex_d08a&snapshot=nyx_720-5312_build_secondaryindex_bc6f