pgsql: Add test case for an archive recovery corner case.

Add test case for an archive recovery corner case.

While I was working on a patch to refactor things around xlog.c, I mixed
up EndOfLogTLI and replayTLI at the end of recovery. As a result, if you
recovered to a point with a lower-numbered timeline in a WAL segment
that has a higher TLI in the filename, the end-of-recovery WAL record
was created with invalid PrevTimeLineId. I noticed that while
self-reviewing, but no tests failed. So add a test to cover that corner
case.

Thanks to Amul Sul who also submitted a test case for the same corner
case, although this patch is different from that.

Reviewed-by: Amul Sul, Michael Paquier
Discussion: https://www.postgresql.org/message-id/52bc9ccd-8591-431b-0086-15d9acf25a3f@iki.fi
Discussion:
https://www.postgresql.org/message-id/CAAJ_b94Vjt5cXGza_1MkjLQWciNdEemsmiWuQj0d%3DM7JfjAa1g%40mail.gmail.com

Branch
------
master

Details
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https://git.postgresql.org/pg/commitdiff/50e5bc582a4371a88218078a2c651d901bf87d96

Modified Files
--------------
src/test/recovery/t/028_pitr_timelines.pl | 176 ++++++++++++++++++++++++++++++
1 file changed, 176 insertions(+)