pgsql: Install a more correct fix in the timestamp and timestamptz

Log Message:
-----------
Install a more correct fix in the timestamp and timestamptz regression tests:
remove duplicated tests in timestamp, and complete timestamptz with the tests
that were missing to more closely mirror timestamp.

Modified Files:
--------------
    pgsql/src/test/regress/expected:
        timestamp.out (r1.34 -> r1.35)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/timestamp.out.diff?r1=1.34&r2=1.35)
        timestamptz.out (r1.24 -> r1.25)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/timestamptz.out.diff?r1=1.24&r2=1.25)
    pgsql/src/test/regress/sql:
        timestamp.sql (r1.19 -> r1.20)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/timestamp.sql.diff?r1=1.19&r2=1.20)
        timestamptz.sql (r1.12 -> r1.13)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/timestamptz.sql.diff?r1=1.12&r2=1.13)