pgsql: Remove shadow variables linked to RedoRecPtr in xlog.c

Remove shadow variables linked to RedoRecPtr in xlog.c

This changes the routines in charge of recycling WAL segments past the
last redo LSN to not use anymore "RedoRecPtr" as a local variable, which
is also available in the context of the session as a static declaration,
replacing it with "lastredoptr". This confusion has been introduced by
d9fadbf, so backpatch down to v11 like the other commit.

Thanks to Tom Lane, Robert Haas, Alvaro Herrera, Mark Dilger and Kyotaro
Horiguchi for the input provided.

Author: Ranier Vilela
Discussion: https://postgr.es/m/MN2PR18MB2927F7B5F690065E1194B258E35D0@MN2PR18MB2927.namprd18.prod.outlook.com
Backpatch-through: 11

Branch
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REL_12_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/35c01529b8c9d8f168379639b4f37227d768d313

Modified Files
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src/backend/access/transam/xlog.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)