Add some defenses against functions declared to return set that don't actually follow the protocol; per example from Kris Jurka.
Add some defenses against functions declared to return set that don't
actually follow the protocol; per example from Kris Jurka.

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