Revert "Fix PostgreSQL 11 build failure"
Revert "Fix PostgreSQL 11 build failure"

This reverts commit e7bfbc80bbaca547167d645be11db24c8922385f.

In PostgreSQL mailing-list, it is decided to allow usage of existing API to not
break extensions. Also using AllocSetContextCreateExtended was not correct fix
anyway, because that skips some error checks.

Discussion: 63a8e02f4c70908133250cee38d294d8ebb31c83@alap3.anarazel.de

citusdata/postgresql-hll,aggregateknowledge/postgresql-hll,citusdata/postgresql-hll,aggregateknowledge/postgresql-hll