Add support for delimited identifiers. Include new exclusive state "xd". Remove unused ScanString variable and code.
Add support for delimited identifiers. Include new exclusive state "xd".
Remove unused ScanString variable and code.

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