pgsql: Tighten up a couple of regression test cases that can have

Log Message:
-----------
Tighten up a couple of regression test cases that can have platform-dependent
results due to underspecified ordering.  Per report from buildfarm member
pika.

Modified Files:
--------------
    pgsql/src/test/regress/expected:
        window.out (r1.1 -> r1.2)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/window.out?r1=1.1&r2=1.2)
    pgsql/src/test/regress/sql:
        window.sql (r1.1 -> r1.2)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/window.sql?r1=1.1&r2=1.2)