Fix bugs in interval-to-time conversion: HAVE_INT64_TIMESTAMP case did not work at all, and neither case behaved sanely for negative intervals.
Fix bugs in interval-to-time conversion: HAVE_INT64_TIMESTAMP case did not
work at all, and neither case behaved sanely for negative intervals.

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