Do a CHECK_FOR_INTERRUPTS after emitting a message of less than ERROR severity.  This is to ensure the user can cancel a query that's spitting out lots of notice/warning messages, even if they're coming from a loop that doesn't otherwise contain a CHECK_FOR_INTERRUPTS.  Per gripe from Stephen Frost.
Do a CHECK_FOR_INTERRUPTS after emitting a message of less than ERROR
severity.  This is to ensure the user can cancel a query that's spitting
out lots of notice/warning messages, even if they're coming from a loop
that doesn't otherwise contain a CHECK_FOR_INTERRUPTS.  Per gripe from
Stephen Frost.

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