Revert "Fix the issue when initializing SPIMemReserved."
Revert "Fix the issue when initializing SPIMemReserved."

This reverts commit da4007b24408e90d521c0d1dc9ce79bb5f5027ef which
decreased the memory a SPI function can use, so lots of tests
failed with "insufficient memory reserved for statement".

xinzweb/gpdb,xinzweb/gpdb,yuanzhao/gpdb,50wu/gpdb,jmcatamney/gpdb,lisakowen/gpdb,jmcatamney/gpdb,Chibin/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,edespino/gpdb,xinzweb/gpdb,xinzweb/gpdb,yuanzhao/gpdb,edespino/gpdb,Chibin/gpdb,adam8157/gpdb,ashwinstar/gpdb,lisakowen/gpdb,Chibin/gpdb,edespino/gpdb,adam8157/gpdb,50wu/gpdb,50wu/gpdb,lisakowen/gpdb,yuanzhao/gpdb,Chibin/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,greenplum-db/gpdb,xinzweb/gpdb,adam8157/gpdb,edespino/gpdb,edespino/gpdb,edespino/gpdb,Chibin/gpdb,ashwinstar/gpdb,50wu/gpdb,xinzweb/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,50wu/gpdb,xinzweb/gpdb,50wu/gpdb,edespino/gpdb,Chibin/gpdb,adam8157/gpdb,adam8157/gpdb,yuanzhao/gpdb,Chibin/gpdb,yuanzhao/gpdb,edespino/gpdb,edespino/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,lisakowen/gpdb,lisakowen/gpdb,xinzweb/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,Chibin/gpdb,Chibin/gpdb,adam8157/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,yuanzhao/gpdb,greenplum-db/gpdb,edespino/gpdb,lisakowen/gpdb,adam8157/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,50wu/gpdb,greenplum-db/gpdb,lisakowen/gpdb,lisakowen/gpdb,adam8157/gpdb,yuanzhao/gpdb,50wu/gpdb,Chibin/gpdb,jmcatamney/gpdb