pgsql: Move checking an explicit VARIADIC "any" argument into the parse

Move checking an explicit VARIADIC "any" argument into the parser.

This is more efficient and simpler . It does mean that an untyped NULL
can no longer be used in such cases, which should be mentioned in
Release Notes, but doesn't seem a terrible loss. The workaround is to
cast the NULL to some array type.

Pavel Stehule, reviewed by Jeevan Chalke.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/d26888bc4d1e539a82f21382b0000fe5bbf889d9

Modified Files
--------------
src/backend/catalog/pg_aggregate.c | 4 +++-
src/backend/parser/parse_func.c | 22 ++++++++++++++++++-
src/backend/utils/adt/ruleutils.c | 4 +++-
src/backend/utils/adt/varlena.c | 42 ++++++++++++++----------------------
src/include/parser/parse_func.h | 4 ++--
src/test/regress/expected/text.out | 10 +++++----
src/test/regress/sql/text.sql | 8 +++----
7 files changed, 55 insertions(+), 39 deletions(-)