pgsql: Fix determination of broken LSN in OVERWRITTEN_CONTRECORD

Fix determination of broken LSN in OVERWRITTEN_CONTRECORD

In commit ff9f111bce24 I mixed up inconsistent definitions of the LSN of
the first record in a page, when the previous record ends exactly at the
page boundary. The correct LSN is adjusted to skip the WAL page header;
I failed to use that when setting XLogReaderState->overwrittenRecPtr,
so at WAL replay time VerifyOverwriteContrecord would refuse to let
replay continue past that record.

Backpatch to 10. 9.6 also contains this bug, but it's no longer being
maintained.

Discussion: https://postgr.es/m/45597.1637694259@sss.pgh.pa.us

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/2c3fddcbbd8aa542beec8e3abf3369168517174e

Modified Files
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src/backend/access/transam/xlogreader.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)