pgsql: Allow domains over arrays to match ANYARRAY parameters again.

Allow domains over arrays to match ANYARRAY parameters again.

This use-case was broken in commit 529cb267a6843a6a8190c86b75d091771d99d6a9
of 2010-10-21, in which I commented "For the moment, we just forbid such
matching.  We might later wish to insert an automatic downcast to the
underlying array type, but such a change should also change matching of
domains to ANYELEMENT for consistency".  We still lack consensus about what
to do with ANYELEMENT; but not matching ANYARRAY is a clear loss of
functionality compared to prior releases, so let's go ahead and make that
happen.  Per complaint from Regina Obe and extensive subsequent discussion.

Branch
------
master

Details
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http://git.postgresql.org/pg/commitdiff/b7e8feb33e5d948c66720643fe32cfb06980c3d1

Modified Files
--------------
src/backend/parser/parse_coerce.c    |   87 ++++++++++++++++++++++++++--------
src/test/regress/expected/domain.out |   36 ++++++++++++++
src/test/regress/sql/domain.sql      |    7 +++
3 files changed, 110 insertions(+), 20 deletions(-)