Add SQL/92 "constants" current_date, current_time, and current_timestamp.

 like newline inside quoted strings.

for regress test.

Allow use IDENT as arguments of trigger functions

in upper Executor memory context.

+ BlowawayRelationBuffers(relation, blocknumber)

	where x <> 1 or x isnull
didn't return tuples with x NULL.

Add integer/money arithmetic.