Remove ancient restriction that LIMIT/OFFSET can't contain a sub-select. This was probably protecting some implementation limitation when it was put in, but as far as I can tell the planner and executor have no such assumption anymore; the case seems to work fine.  Per a gripe from Grzegorz Jaskiewicz.
Remove ancient restriction that LIMIT/OFFSET can't contain a sub-select.
This was probably protecting some implementation limitation when it was
put in, but as far as I can tell the planner and executor have no such
assumption anymore; the case seems to work fine.  Per a gripe from
Grzegorz Jaskiewicz.

pavanvd/postgres-xl,greenplum-db/gpdb,postmind-net/postgres-xl,greenplum-db/gpdb,ovr/postgres-xl,50wu/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,techdragon/Postgres-XL,yuanzhao/gpdb,ovr/postgres-xl,yazun/postgres-xl,greenplum-db/gpdb,techdragon/Postgres-XL,edespino/gpdb,yuanzhao/gpdb,zeroae/postgres-xl,zeroae/postgres-xl,yazun/postgres-xl,Chibin/gpdb,ashwinstar/gpdb,50wu/gpdb,jmcatamney/gpdb,yazun/postgres-xl,adam8157/gpdb,snaga/postgres-xl,jmcatamney/gpdb,arcivanov/postgres-xl,oberstet/postgres-xl,Postgres-XL/Postgres-XL,edespino/gpdb,snaga/postgres-xl,xinzweb/gpdb,edespino/gpdb,xinzweb/gpdb,ashwinstar/gpdb,Chibin/gpdb,xinzweb/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,xinzweb/gpdb,adam8157/gpdb,kmjungersen/PostgresXL,50wu/gpdb,edespino/gpdb,arcivanov/postgres-xl,xinzweb/gpdb,greenplum-db/gpdb,lisakowen/gpdb,50wu/gpdb,ashwinstar/gpdb,edespino/gpdb,jmcatamney/gpdb,lisakowen/gpdb,greenplum-db/gpdb,Chibin/gpdb,lisakowen/gpdb,jmcatamney/gpdb,lisakowen/gpdb,lisakowen/gpdb,pavanvd/postgres-xl,oberstet/postgres-xl,snaga/postgres-xl,jmcatamney/gpdb,adam8157/gpdb,tpostgres-projects/tPostgres,jmcatamney/gpdb,edespino/gpdb,lisakowen/gpdb,tpostgres-projects/tPostgres,kmjungersen/PostgresXL,edespino/gpdb,zeroae/postgres-xl,Chibin/gpdb,Chibin/gpdb,adam8157/gpdb,snaga/postgres-xl,techdragon/Postgres-XL,arcivanov/postgres-xl,tpostgres-projects/tPostgres,yazun/postgres-xl,zeroae/postgres-xl,arcivanov/postgres-xl,adam8157/gpdb,xinzweb/gpdb,lisakowen/gpdb,adam8157/gpdb,Postgres-XL/Postgres-XL,adam8157/gpdb,Chibin/gpdb,yuanzhao/gpdb,edespino/gpdb,tpostgres-projects/tPostgres,pavanvd/postgres-xl,edespino/gpdb,kmjungersen/PostgresXL,jmcatamney/gpdb,postmind-net/postgres-xl,Postgres-XL/Postgres-XL,postmind-net/postgres-xl,ovr/postgres-xl,ashwinstar/gpdb,edespino/gpdb,yazun/postgres-xl,Chibin/gpdb,tpostgres-projects/tPostgres,50wu/gpdb,yuanzhao/gpdb,yuanzhao/gpdb,xinzweb/gpdb,techdragon/Postgres-XL,yuanzhao/gpdb,oberstet/postgres-xl,greenplum-db/gpdb,oberstet/postgres-xl,ashwinstar/gpdb,ovr/postgres-xl,techdragon/Postgres-XL,zeroae/postgres-xl,postmind-net/postgres-xl,yuanzhao/gpdb,kmjungersen/PostgresXL,Chibin/gpdb,lisakowen/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,kmjungersen/PostgresXL,oberstet/postgres-xl,50wu/gpdb,Chibin/gpdb,Postgres-XL/Postgres-XL,ashwinstar/gpdb,postmind-net/postgres-xl,greenplum-db/gpdb,arcivanov/postgres-xl,Postgres-XL/Postgres-XL,xinzweb/gpdb,50wu/gpdb,adam8157/gpdb,ovr/postgres-xl,Chibin/gpdb,snaga/postgres-xl,arcivanov/postgres-xl,pavanvd/postgres-xl,50wu/gpdb,pavanvd/postgres-xl,greenplum-db/gpdb