Salvage a little bit of work from a failed patch: simplify and speed up set_rel_width().  The code had been catering for the possibility of different varnos in the relation targetlist, but this is impossible for a base relation (and if it were possible, putting all the widths in the same RelOptInfo would be wrong anyway).
Salvage a little bit of work from a failed patch: simplify and speed up
set_rel_width().  The code had been catering for the possibility of different
varnos in the relation targetlist, but this is impossible for a base relation
(and if it were possible, putting all the widths in the same RelOptInfo would
be wrong anyway).

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