Initial index build time increase for Bloom filter tests

Seeing Initial build time shows ~60%-70% increase for Plasma bloom filter tests between 7.1.0-1250 vs 7.1.0-1345

One of the run 

Test : Initial index (min), 1 bucket x 100M, 4 2i Indexes, 100K KV ops/sec, 128 byte keysize, Insert Only Workload, PLASMA With Bloom filter

7.1.0-1250 : 60.8

7.1.0-1345 : 102

cbmonitor : http://cbmonitor.sc.couchbase.com/reports/html/?snapshot=hemera_710-1345_build_secondaryindex_6070&snapshot=hemera_710-1250_build_secondaryindex_a7a2 

job : http://perf.jenkins.couchbase.com/job/hemera/2812/consoleFull 

change log

http://changelog.build.couchbase.com/?product=couchbase-server&fromVersion=7.1.0&fromBuild=1250&toVersion=7.1.0&toBuild=1345&f_HdrHistogram_c=off&f_asterixdb=off&f_backup=off&f_build=off&f_cbas=off&f_cbas-core=off&f_cbas-ui=off&f_cbauth=off&f_cbbs=off&f_cbft=off&f_cbftx=off&f_cbgt=off&f_cbsummary=off&f_chronicle=off&f_couchbase-cli=off&f_couchdb=off&f_couchstore=off&f_docloader=off&f_eventing=off&f_eventing-ee=off&f_forestdb=off&f_geocouch=off&f_gomemcached=off&f_gometa=off&f_goxdcr=off&f_indexing=on&f_kv_engine=off&f_magma=off&f_n1fty=off&f_nitro=off&f_ns_server=off&f_phosphor=off&f_plasma=off&f_platform=off&f_product-metadata=off&f_query=off&f_query-ee=off&f_query-ui=off&f_subjson=off&f_testrunner=off&f_text=off&f_tlm=off&f_udf-api=off&f_voltron=off