pgsql: Add some checks on "char"-type columns to type_sanity and opr_sa

Add some checks on "char"-type columns to type_sanity and opr_sanity.

I noticed that the sanity checks in the regression tests omitted to
check a couple of "poor man's enum" columns that you'd reasonably
expect them to check.

There are other "char"-type columns in system catalogs that are not
covered by either type_sanity or opr_sanity, e.g. pg_rewrite.ev_type.
However, those catalogs are not populated with any manually-created
data during bootstrap, so it seems less necessary to check them
this way.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/3ef16c46fb3a64c150a3b42c3cc4a8538a12ff3f

Modified Files
--------------
src/test/regress/expected/opr_sanity.out | 4 +++-
src/test/regress/expected/type_sanity.out | 4 +++-
src/test/regress/sql/opr_sanity.sql | 4 +++-
src/test/regress/sql/type_sanity.sql | 4 +++-
4 files changed, 12 insertions(+), 4 deletions(-)