Avoid unnecessary work when stats collection is disabled.  Tighten search loop in pgstat_initstats.  Per report from Gavin Sherry.
Avoid unnecessary work when stats collection is disabled.  Tighten
search loop in pgstat_initstats.  Per report from Gavin Sherry.

CraigHarris/gpdb,xinzweb/gpdb,rvs/gpdb,lisakowen/gpdb,lintzc/gpdb,ashwinstar/gpdb,cjcjameson/gpdb,chrishajas/gpdb,lintzc/gpdb,tangp3/gpdb,Quikling/gpdb,edespino/gpdb,zaksoup/gpdb,foyzur/gpdb,pavanvd/postgres-xl,Quikling/gpdb,ovr/postgres-xl,50wu/gpdb,ashwinstar/gpdb,lisakowen/gpdb,greenplum-db/gpdb,edespino/gpdb,kaknikhil/gpdb,postmind-net/postgres-xl,yazun/postgres-xl,snaga/postgres-xl,Postgres-XL/Postgres-XL,foyzur/gpdb,zeroae/postgres-xl,edespino/gpdb,jmcatamney/gpdb,kmjungersen/PostgresXL,Quikling/gpdb,kaknikhil/gpdb,foyzur/gpdb,techdragon/Postgres-XL,chrishajas/gpdb,zeroae/postgres-xl,kmjungersen/PostgresXL,edespino/gpdb,kaknikhil/gpdb,lpetrov-pivotal/gpdb,adam8157/gpdb,yazun/postgres-xl,lpetrov-pivotal/gpdb,atris/gpdb,cjcjameson/gpdb,lisakowen/gpdb,kmjungersen/PostgresXL,janebeckman/gpdb,postmind-net/postgres-xl,yazun/postgres-xl,rvs/gpdb,foyzur/gpdb,0x0FFF/gpdb,zaksoup/gpdb,lintzc/gpdb,adam8157/gpdb,lisakowen/gpdb,zaksoup/gpdb,yuanzhao/gpdb,atris/gpdb,randomtask1155/gpdb,jmcatamney/gpdb,xuegang/gpdb,50wu/gpdb,kmjungersen/PostgresXL,xinzweb/gpdb,rubikloud/gpdb,rvs/gpdb,ovr/postgres-xl,rubikloud/gpdb,lintzc/gpdb,Postgres-XL/Postgres-XL,yazun/postgres-xl,50wu/gpdb,Quikling/gpdb,greenplum-db/gpdb,yazun/postgres-xl,Chibin/gpdb,adam8157/gpdb,snaga/postgres-xl,Quikling/gpdb,oberstet/postgres-xl,ahachete/gpdb,Chibin/gpdb,zeroae/postgres-xl,zaksoup/gpdb,cjcjameson/gpdb,CraigHarris/gpdb,arcivanov/postgres-xl,arcivanov/postgres-xl,cjcjameson/gpdb,techdragon/Postgres-XL,xuegang/gpdb,randomtask1155/gpdb,lisakowen/gpdb,tangp3/gpdb,lintzc/gpdb,randomtask1155/gpdb,tpostgres-projects/tPostgres,adam8157/gpdb,edespino/gpdb,zeroae/postgres-xl,royc1/gpdb,tpostgres-projects/tPostgres,atris/gpdb,rvs/gpdb,xinzweb/gpdb,janebeckman/gpdb,ahachete/gpdb,yuanzhao/gpdb,janebeckman/gpdb,snaga/postgres-xl,yuanzhao/gpdb,chrishajas/gpdb,adam8157/gpdb,lintzc/gpdb,cjcjameson/gpdb,lisakowen/gpdb,xinzweb/gpdb,rvs/gpdb,0x0FFF/gpdb,techdragon/Postgres-XL,foyzur/gpdb,greenplum-db/gpdb,lpetrov-pivotal/gpdb,Chibin/gpdb,foyzur/gpdb,CraigHarris/gpdb,ovr/postgres-xl,xinzweb/gpdb,randomtask1155/gpdb,kaknikhil/gpdb,snaga/postgres-xl,rubikloud/gpdb,janebeckman/gpdb,xuegang/gpdb,adam8157/gpdb,xinzweb/gpdb,adam8157/gpdb,zaksoup/gpdb,Chibin/gpdb,ashwinstar/gpdb,0x0FFF/gpdb,atris/gpdb,50wu/gpdb,xuegang/gpdb,cjcjameson/gpdb,lintzc/gpdb,tpostgres-projects/tPostgres,jmcatamney/gpdb,adam8157/gpdb,0x0FFF/gpdb,janebeckman/gpdb,edespino/gpdb,rubikloud/gpdb,foyzur/gpdb,randomtask1155/gpdb,postmind-net/postgres-xl,tangp3/gpdb,pavanvd/postgres-xl,zaksoup/gpdb,xinzweb/gpdb,CraigHarris/gpdb,Postgres-XL/Postgres-XL,greenplum-db/gpdb,lisakowen/gpdb,ahachete/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,rubikloud/gpdb,ahachete/gpdb,foyzur/gpdb,janebeckman/gpdb,royc1/gpdb,yuanzhao/gpdb,kmjungersen/PostgresXL,rvs/gpdb,rubikloud/gpdb,CraigHarris/gpdb,tpostgres-projects/tPostgres,lpetrov-pivotal/gpdb,jmcatamney/gpdb,ahachete/gpdb,kaknikhil/gpdb,rvs/gpdb,rvs/gpdb,kaknikhil/gpdb,pavanvd/postgres-xl,xuegang/gpdb,royc1/gpdb,0x0FFF/gpdb,lintzc/gpdb,yuanzhao/gpdb,xuegang/gpdb,zaksoup/gpdb,snaga/postgres-xl,lintzc/gpdb,atris/gpdb,edespino/gpdb,jmcatamney/gpdb,tangp3/gpdb,tangp3/gpdb,randomtask1155/gpdb,Chibin/gpdb,cjcjameson/gpdb,royc1/gpdb,pavanvd/postgres-xl,royc1/gpdb,lpetrov-pivotal/gpdb,cjcjameson/gpdb,50wu/gpdb,Postgres-XL/Postgres-XL,oberstet/postgres-xl,cjcjameson/gpdb,yuanzhao/gpdb,Quikling/gpdb,oberstet/postgres-xl,yuanzhao/gpdb,atris/gpdb,greenplum-db/gpdb,lpetrov-pivotal/gpdb,ashwinstar/gpdb,janebeckman/gpdb,cjcjameson/gpdb,atris/gpdb,0x0FFF/gpdb,chrishajas/gpdb,edespino/gpdb,royc1/gpdb,ashwinstar/gpdb,janebeckman/gpdb,greenplum-db/gpdb,arcivanov/postgres-xl,royc1/gpdb,atris/gpdb,Chibin/gpdb,50wu/gpdb,janebeckman/gpdb,postmind-net/postgres-xl,postmind-net/postgres-xl,xuegang/gpdb,Quikling/gpdb,CraigHarris/gpdb,ahachete/gpdb,randomtask1155/gpdb,rvs/gpdb,techdragon/Postgres-XL,kaknikhil/gpdb,ashwinstar/gpdb,techdragon/Postgres-XL,yuanzhao/gpdb,ovr/postgres-xl,CraigHarris/gpdb,50wu/gpdb,Postgres-XL/Postgres-XL,zeroae/postgres-xl,ovr/postgres-xl,Quikling/gpdb,jmcatamney/gpdb,lpetrov-pivotal/gpdb,lpetrov-pivotal/gpdb,kaknikhil/gpdb,kaknikhil/gpdb,tangp3/gpdb,arcivanov/postgres-xl,chrishajas/gpdb,xuegang/gpdb,kaknikhil/gpdb,oberstet/postgres-xl,tangp3/gpdb,rubikloud/gpdb,rubikloud/gpdb,arcivanov/postgres-xl,ashwinstar/gpdb,Chibin/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,ahachete/gpdb,jmcatamney/gpdb,Chibin/gpdb,0x0FFF/gpdb,royc1/gpdb,Chibin/gpdb,randomtask1155/gpdb,ahachete/gpdb,50wu/gpdb,yuanzhao/gpdb,xinzweb/gpdb,rvs/gpdb,edespino/gpdb,chrishajas/gpdb,tpostgres-projects/tPostgres,oberstet/postgres-xl,zaksoup/gpdb,xuegang/gpdb,edespino/gpdb,lisakowen/gpdb,Quikling/gpdb,chrishajas/gpdb,arcivanov/postgres-xl,janebeckman/gpdb,Chibin/gpdb,pavanvd/postgres-xl,chrishajas/gpdb,Quikling/gpdb,CraigHarris/gpdb,0x0FFF/gpdb,CraigHarris/gpdb,yuanzhao/gpdb,tangp3/gpdb