pgsql: Add support for cross-type hashing in hashed subplans (hashed

Log Message:
-----------
Add support for cross-type hashing in hashed subplans (hashed IN/NOT IN cases
that aren't turned into true joins). Since this is the last missing bit of
infrastructure, go ahead and fill out the hash integer_ops and float_ops
opfamilies with cross-type operators. The operator family project is now
DONE ... er, except for documentation ...

Modified Files:
--------------
pgsql/src/backend/executor:
execGrouping.c (r1.24 -> r1.25)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/execGrouping.c.diff?r1=1.24&r2=1.25)
nodeSubplan.c (r1.84 -> r1.85)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/nodeSubplan.c.diff?r1=1.84&r2=1.85)
pgsql/src/backend/optimizer/plan:
subselect.c (r1.117 -> r1.118)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/plan/subselect.c.diff?r1=1.117&r2=1.118)
pgsql/src/backend/optimizer/util:
pathnode.c (r1.137 -> r1.138)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/util/pathnode.c.diff?r1=1.137&r2=1.138)
pgsql/src/include/catalog:
catversion.h (r1.380 -> r1.381)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h.diff?r1=1.380&r2=1.381)
pg_amop.h (r1.78 -> r1.79)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_amop.h.diff?r1=1.78&r2=1.79)
pg_operator.h (r1.149 -> r1.150)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_operator.h.diff?r1=1.149&r2=1.150)
pgsql/src/include/executor:
executor.h (r1.135 -> r1.136)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/executor/executor.h.diff?r1=1.135&r2=1.136)
pgsql/src/include/nodes:
execnodes.h (r1.166 -> r1.167)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/execnodes.h.diff?r1=1.166&r2=1.167)
pgsql/src/test/regress/expected:
opr_sanity.out (r1.73 -> r1.74)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/opr_sanity.out.diff?r1=1.73&r2=1.74)
pgsql/src/test/regress/sql:
opr_sanity.sql (r1.59 -> r1.60)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/opr_sanity.sql.diff?r1=1.59&r2=1.60)