pgsql: Add aggregate_with_argtypes and use it consistently

Add aggregate_with_argtypes and use it consistently

This works like function_with_argtypes, but aggregates allow slightly
different arguments.

Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/b999c247a5df4110a2ae20b01f0f686840169875

Modified Files
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src/backend/parser/gram.y | 74 +++++++++++++++++++++++++++--------------------
1 file changed, 42 insertions(+), 32 deletions(-)