Correct DELETED tuple reference pg_decode_change_v1

[robert-pang]

When I build and run wal2json's regression tests, test "pk" fails and the Postgres backend process crashes with this error:

2022-09-21 18:05:54.488 PDT [4251] LOG:  server process (PID 4378) was terminated by signal 4: Illeg
al instruction
2022-09-21 18:05:54.488 PDT [4251] DETAIL:  Failed process was running: SELECT data FROM pg_logical_
slot_peek_changes('regression_slot', NULL, NULL, 'format-version', '1', 'pretty-print', '1', 'includ
e-typmod', '0', 'include-pk', '1');

Upon some debugging, I notice that wal2json references newtuple under the REORDER_BUFFER_CHANGE_DELETE case in pg_decode_change_v1() when calling pk_to_stringinfo() but it seems like we should use the old tuple. If I replace it with oldtuple, the test passes.

Can we confirm if we should pass oldtuple to pk_to_stringinfo()?

[robert-pang]

Any comment if the proposed change is valid?

[robert-pang]

Thank you for reviewing this PR and merging it.