Fix handling of full outer joins by partitionwise join

When Who What
2020-04-08 02:12:50 Tom Lane (tgl) Closed in commitfest 2020-03 with status: Committed
2020-04-08 02:12:50 Tom Lane (tgl) Changed committer to tgl
2020-04-04 16:12:43 Tom Lane (tgl) New status: Needs review
2020-04-03 21:13:55 Tom Lane (tgl) Added tgl as reviewer
2020-04-03 21:03:23 Tom Lane (tgl) New status: Waiting on Author
2020-02-01 12:51:28 Tomas Vondra (fuzzycz) Closed in commitfest 2020-01 with status: Moved to next CF
2019-11-29 06:34:15 Michael Paquier (michael-kun) Closed in commitfest 2019-11 with status: Moved to next CF
2019-11-06 18:39:18 Tom Lane (tgl) New status: Needs review
2019-11-05 16:49:06 Tom Lane (tgl) New status: Waiting on Author
2019-10-15 01:38:20 Justin Pryzby (justinpryzby) Added justinpryzby as reviewer
2019-09-04 08:46:05 Richard Guo (richardguo) Added richardguo as reviewer
2019-09-04 01:50:52 Amit Langote (amitlan) Changed authors to Amit Langote (amitlan)
2019-09-04 01:50:41 Amit Langote (amitlan) Attached mail thread CA+HiwqG2WVUGmLJqtR0tPFhniO=H=9qQ+Z3L_ZC+Y3-EVQHFGg@mail.gmail.com
2019-09-04 01:50:41 Amit Langote (amitlan) Created patch record