pgsql: Allow OLD and NEW in multi-row VALUES within rules.

Allow OLD and NEW in multi-row VALUES within rules.

Now that we have LATERAL, it's fairly painless to allow this case, which
was left as a TODO in the original multi-row VALUES implementation.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/092d7ded29f36b0539046b23b81b9f0bf2d637f1

Modified Files
--------------
src/backend/optimizer/path/allpaths.c | 4 +-
src/backend/parser/analyze.c | 46 ++++++++-----------
src/backend/parser/parse_relation.c | 3 +-
src/backend/utils/adt/ruleutils.c | 57 ++++++++++++++++++------
src/include/nodes/parsenodes.h | 2 +-
src/include/parser/parse_relation.h | 1 +
src/test/regress/expected/rules.out | 78 +++++++++++++++++++++++++++++++++
src/test/regress/sql/rules.sql | 20 ++++++++
8 files changed, 164 insertions(+), 47 deletions(-)