pgsql: Fix LATERAL references to target table of UPDATE/DELETE.

Fix LATERAL references to target table of UPDATE/DELETE.

I failed to think much about UPDATE/DELETE when implementing LATERAL :-(.
The implemented behavior ended up being that subqueries in the FROM or
USING clause (respectively) could access the update/delete target table as
though it were a lateral reference; which seems fine if they said LATERAL,
but certainly ought to draw an error if they didn't.  Fix it so you get a
suitable error when you omit LATERAL.  Per report from Emre Hasegeli.

Branch
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REL9_3_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/0a43e5466ca03fce433309c6de2a4272b79c1abb

Modified Files
--------------
src/backend/parser/analyze.c        |   21 +++++++++++++++
src/backend/parser/parse_clause.c   |    4 +++
src/backend/parser/parse_relation.c |    4 +++
src/test/regress/expected/join.out  |   48 +++++++++++++++++++++++++++++++++++
src/test/regress/sql/join.sql       |   18 +++++++++++++
5 files changed, 95 insertions(+)