pgsql: Clean up sloppy maintenance of regression test schedule files.

Clean up sloppy maintenance of regression test schedule files.

The partition_join test was added to a parallel group that was already
at the maximum of 20 concurrent tests. The hash_func test wasn't
added to serial_schedule at all. The identity and partition_join tests
were added to serial_schedule with the aid of a dartboard, rather than
maintaining consistency with parallel_schedule.

There are proposals afoot to make these sorts of errors harder to make,
but in the meantime let's fix the ones already in place.

Discussion: https://postgr.es/m/a37e9c57-22d4-1b82-1270-4501cd2e984e@2ndquadrant.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/1fdab4d5aa47d8a2bb29ccb1122b0158f6db221f

Modified Files
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src/test/regress/parallel_schedule | 4 ++--
src/test/regress/serial_schedule | 5 +++--
2 files changed, 5 insertions(+), 4 deletions(-)