Limit removing and replacing the CollateExpr in coerce_to_target_type on remote nodes
Limit removing and replacing the CollateExpr in coerce_to_target_type on remote nodes

Related to commit 188f1b928205bf33ce29887eeeee26ce9227908f on PostgreSQL
9.1 stable branch, we can only do this ugly operation on remote nodes
as there are consequences on executor side of local Coordinator.

pavanvd/postgres-xl,pavanvd/postgres-xl,Postgres-XL/Postgres-XL,arcivanov/postgres-xl,Postgres-XL/Postgres-XL,techdragon/Postgres-XL,arcivanov/postgres-xl,postmind-net/postgres-xl,kmjungersen/PostgresXL,snaga/postgres-xl,ovr/postgres-xl,postmind-net/postgres-xl,yazun/postgres-xl,zeroae/postgres-xl,yazun/postgres-xl,techdragon/Postgres-XL,kmjungersen/PostgresXL,Postgres-XL/Postgres-XL,oberstet/postgres-xl,Postgres-XL/Postgres-XL,ovr/postgres-xl,zeroae/postgres-xl,snaga/postgres-xl,ovr/postgres-xl,kmjungersen/PostgresXL,yazun/postgres-xl,ovr/postgres-xl,arcivanov/postgres-xl,kmjungersen/PostgresXL,snaga/postgres-xl,yazun/postgres-xl,oberstet/postgres-xl,techdragon/Postgres-XL,ovr/postgres-xl,techdragon/Postgres-XL,postmind-net/postgres-xl,oberstet/postgres-xl,pavanvd/postgres-xl,yazun/postgres-xl,techdragon/Postgres-XL,oberstet/postgres-xl,zeroae/postgres-xl,arcivanov/postgres-xl,pavanvd/postgres-xl,postmind-net/postgres-xl,oberstet/postgres-xl,postmind-net/postgres-xl,arcivanov/postgres-xl,snaga/postgres-xl,zeroae/postgres-xl,kmjungersen/PostgresXL,snaga/postgres-xl,arcivanov/postgres-xl,Postgres-XL/Postgres-XL,zeroae/postgres-xl,pavanvd/postgres-xl