pgsql: Fix ruleutils.c's dumping of whole-row Vars in ROW() and VALUES(

Fix ruleutils.c's dumping of whole-row Vars in ROW() and VALUES() contexts.

Normally ruleutils prints a whole-row Var as "foo.*". We already knew that
that doesn't work at top level of a SELECT list, because the parser would
treat the "*" as a directive to expand the reference into separate columns,
not a whole-row Var. However, Joshua Yanovski points out in bug #13776
that the same thing happens at top level of a ROW() construct; and some
nosing around in the parser shows that the same is true in VALUES().
Hence, apply the same workaround already devised for the SELECT-list case,
namely to add a forced cast to the appropriate rowtype in these cases.
(The alternative of just printing "foo" was rejected because it is
difficult to avoid ambiguity against plain columns named "foo".)

Back-patch to all supported branches.

Branch
------
REL9_5_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/0489a048d3914e4d5f89c91ac604350b9392e6fa

Modified Files
--------------
src/backend/utils/adt/ruleutils.c | 35 +++++++++--
src/test/regress/expected/create_view.out | 91 +++++++++++++++++++++++++++++
src/test/regress/sql/create_view.sql | 18 ++++++
3 files changed, 139 insertions(+), 5 deletions(-)