Small optimisation to Columns subset serialization
Small optimisation to Columns subset serialization

It is possible to disambiguate the small serialization
format from the large with fewer bytes. Prior to this patch
we serialized -1L for the small coding bitmap, however this
value can instead by the column size delta, and it is entirely
consistent: zero means no columns missing in both formats;
if any are missing, we use the size of the superset to decide.

krummas/cassandra,thobbs/cassandra,modempachev4/kassandra,adejanovski/cassandra,bcoverston/cassandra,guard163/cassandra,jasonstack/cassandra,iamaleksey/cassandra,pauloricardomg/cassandra,stef1927/cassandra,stef1927/cassandra,nutbunnies/cassandra,modempachev4/kassandra,swps/cassandra,bdeggleston/cassandra,juiceblender/cassandra,cooldoger/cassandra,guard163/cassandra,instaclustr/cassandra,yhnishi/cassandra,driftx/cassandra,joesiewert/cassandra,hengxin/cassandra,blambov/cassandra,bdeggleston/cassandra,yonglehou/cassandra,rmarchei/cassandra,aarushi12002/cassandra,yangzhe1991/cassandra,RyanMagnusson/cassandra,jeromatron/cassandra,ben-manes/cassandra,jrwest/cassandra,Jaumo/cassandra,krummas/cassandra,WorksApplications/cassandra,hhorii/cassandra,weideng1/cassandra,fengshao0907/cassandra-1,michaelsembwever/cassandra,pthomaid/cassandra,ptnapoleon/cassandra,kgreav/cassandra,jasobrown/cassandra,jbellis/cassandra,ifesdjeen/cassandra,mambocab/cassandra,vaibhi9/cassandra,nutbunnies/cassandra,newrelic-forks/cassandra,blambov/cassandra,spodkowinski/cassandra,blambov/cassandra,jasobrown/cassandra,jasobrown/cassandra,weideng1/cassandra,tongjixianing/projects,thobbs/cassandra,Jollyplum/cassandra,ifesdjeen/cassandra,scylladb/scylla-tools-java,yangzhe1991/cassandra,scylladb/scylla-tools-java,blambov/cassandra,jeffjirsa/cassandra,ben-manes/cassandra,thelastpickle/cassandra,jeromatron/cassandra,caidongyun/cassandra,thelastpickle/cassandra,mshuler/cassandra,aweisberg/cassandra,yhnishi/cassandra,rdio/cassandra,ptnapoleon/cassandra,bcoverston/cassandra,codefollower/Cassandra-Research,aarushi12002/cassandra,yukim/cassandra,instaclustr/cassandra,exoscale/cassandra,szhou1234/cassandra,yukim/cassandra,blerer/cassandra,fengshao0907/Cassandra-Research,ptnapoleon/cassandra,adelapena/cassandra,phact/cassandra,scylladb/scylla-tools-java,nitsanw/cassandra,regispl/cassandra,a-buck/cassandra,jasonstack/cassandra,szhou1234/cassandra,adelapena/cassandra,mkjellman/cassandra,apache/cassandra,mshuler/cassandra,weipinghe/cassandra,ollie314/cassandra,WorksApplications/cassandra,chbatey/cassandra-1,nutbunnies/cassandra,chbatey/cassandra-1,snazy/cassandra,snazy/cassandra,strapdata/cassandra,driftx/cassandra,vramaswamy456/cassandra,a-buck/cassandra,pthomaid/cassandra,blerer/cassandra,szhou1234/cassandra,RyanMagnusson/cassandra,exoscale/cassandra,aureagle/cassandra,juiceblender/cassandra,aweisberg/cassandra,jasonwee/cassandra,beobal/cassandra,tongjixianing/projects,jeromatron/cassandra,chbatey/cassandra-1,bcoverston/cassandra,rmarchei/cassandra,swps/cassandra,tjake/cassandra,josh-mckenzie/cassandra,weipinghe/cassandra,yonglehou/cassandra,darach/cassandra,a-buck/cassandra,pcmanus/cassandra,pkdevbox/cassandra,stef1927/cassandra,helena/cassandra,aweisberg/cassandra,thobbs/cassandra,darach/cassandra,Jollyplum/cassandra,ejankan/cassandra,tommystendahl/cassandra,carlyeks/cassandra,sedulam/CASSANDRA-12201,fengshao0907/cassandra-1,instaclustr/cassandra,fengshao0907/Cassandra-Research,vaibhi9/cassandra,whitepages/cassandra,christian-esken/cassandra,clohfink/cassandra,sivikt/cassandra,DikangGu/cassandra,macintoshio/cassandra,pkdevbox/cassandra,GabrielNicolasAvellaneda/cassandra,mike-tr-adamson/cassandra,pkdevbox/cassandra,darach/cassandra,apache/cassandra,juiceblender/cassandra,sharvanath/cassandra,tjake/cassandra,aureagle/cassandra,mkjellman/cassandra,josh-mckenzie/cassandra,spodkowinski/cassandra,juiceblender/cassandra,bmel/cassandra,helena/cassandra,kgreav/cassandra,apache/cassandra,modempachev4/kassandra,adelapena/cassandra,Instagram/cassandra,jrwest/cassandra,ptuckey/cassandra,AtwooTM/cassandra,knifewine/cassandra,jeffjirsa/cassandra,adejanovski/cassandra,szhou1234/cassandra,jbellis/cassandra,newrelic-forks/cassandra,knifewine/cassandra,bmel/cassandra,belliottsmith/cassandra,spodkowinski/cassandra,mike-tr-adamson/cassandra,regispl/cassandra,nitsanw/cassandra,DikangGu/cassandra,tjake/cassandra,knifewine/cassandra,driftx/cassandra,Jaumo/cassandra,exoscale/cassandra,vaibhi9/cassandra,krummas/cassandra,RyanMagnusson/cassandra,jeffjirsa/cassandra,scylladb/scylla-tools-java,pauloricardomg/cassandra,thelastpickle/cassandra,dongjiaqiang/cassandra,instaclustr/cassandra,jeffjirsa/cassandra,mkjellman/cassandra,Imran-C/cassandra,belliottsmith/cassandra,GabrielNicolasAvellaneda/cassandra,Jollyplum/cassandra,fengshao0907/Cassandra-Research,blerer/cassandra,tommystendahl/cassandra,bmel/cassandra,cooldoger/cassandra,DikangGu/cassandra,regispl/cassandra,pcmanus/cassandra,macintoshio/cassandra,ptuckey/cassandra,sedulam/CASSANDRA-12201,aureagle/cassandra,guard163/cassandra,aboudreault/cassandra,phact/cassandra,bcoverston/cassandra,ejankan/cassandra,sharvanath/cassandra,tjake/cassandra,clohfink/cassandra,GabrielNicolasAvellaneda/cassandra,yhnishi/cassandra,scaledata/cassandra,mshuler/cassandra,josh-mckenzie/cassandra,jasonwee/cassandra,michaelsembwever/cassandra,AtwooTM/cassandra,codefollower/Cassandra-Research,sivikt/cassandra,josh-mckenzie/cassandra,yukim/cassandra,weipinghe/cassandra,dongjiaqiang/cassandra,jasonstack/cassandra,christian-esken/cassandra,cooldoger/cassandra,Instagram/cassandra,belliottsmith/cassandra,blerer/cassandra,spodkowinski/cassandra,mike-tr-adamson/cassandra,michaelsembwever/cassandra,jrwest/cassandra,ifesdjeen/cassandra,aweisberg/cassandra,ollie314/cassandra,dongjiaqiang/cassandra,ifesdjeen/cassandra,mambocab/cassandra,jasobrown/cassandra,beobal/cassandra,bdeggleston/cassandra,macintoshio/cassandra,aboudreault/cassandra,Instagram/cassandra,vramaswamy456/cassandra,clohfink/cassandra,mambocab/cassandra,yonglehou/cassandra,bpupadhyaya/cassandra,caidongyun/cassandra,kgreav/cassandra,snazy/cassandra,hhorii/cassandra,newrelic-forks/cassandra,driftx/cassandra,krummas/cassandra,beobal/cassandra,Instagram/cassandra,belliottsmith/cassandra,mike-tr-adamson/cassandra,vramaswamy456/cassandra,hengxin/cassandra,bpupadhyaya/cassandra,sedulam/CASSANDRA-12201,rdio/cassandra,bdeggleston/cassandra,Imran-C/cassandra,tommystendahl/cassandra,clohfink/cassandra,kgreav/cassandra,rdio/cassandra,ben-manes/cassandra,hhorii/cassandra,whitepages/cassandra,joesiewert/cassandra,carlyeks/cassandra,mshuler/cassandra,tongjixianing/projects,tommystendahl/cassandra,apache/cassandra,aarushi12002/cassandra,strapdata/cassandra,Imran-C/cassandra,ptuckey/cassandra,fengshao0907/cassandra-1,AtwooTM/cassandra,nitsanw/cassandra,pcmanus/cassandra,adejanovski/cassandra,pauloricardomg/cassandra,ejankan/cassandra,scaledata/cassandra,joesiewert/cassandra,pthomaid/cassandra,ollie314/cassandra,pauloricardomg/cassandra,sharvanath/cassandra,christian-esken/cassandra,thelastpickle/cassandra,scaledata/cassandra,snazy/cassandra,aboudreault/cassandra,carlyeks/cassandra,WorksApplications/cassandra,caidongyun/cassandra,bpupadhyaya/cassandra,helena/cassandra,strapdata/cassandra,WorksApplications/cassandra,beobal/cassandra,yangzhe1991/cassandra,adelapena/cassandra,iamaleksey/cassandra,hengxin/cassandra,rmarchei/cassandra,iamaleksey/cassandra,iamaleksey/cassandra,jbellis/cassandra,michaelsembwever/cassandra,weideng1/cassandra,yukim/cassandra,phact/cassandra,mkjellman/cassandra,codefollower/Cassandra-Research,swps/cassandra,stef1927/cassandra,cooldoger/cassandra,jasonwee/cassandra,whitepages/cassandra,jrwest/cassandra,strapdata/cassandra,sivikt/cassandra,Jaumo/cassandra