pgsql: Reject currtid2() on unlogged tables during recovery.

Reject currtid2() on unlogged tables during recovery.

Commit 1e707d32564 made COPY TO report a proper error for unlogged
tables during recovery. currtid2() has the same problem: it reads the
table directly without going through the planner, so on a standby it
failed with a low-level error for an unlogged table:

ERROR: could not open file "base/5/16384": No such file or directory

Check for this case and report the same error as SELECT. No test is
added, as currtid2() is an undocumented internal function.

Backpatch to all supported versions, like commit 1e707d32564.

Reported-by: Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
Author: Jim Jones <jim(dot)jones(at)uni-muenster(dot)de>
Discussion: https://postgr.es/m/CAD21AoDNa7pL760_23AN_wYPMkWXCt+Kw0_vJAcci4R5DoCQGg@mail.gmail.com
Backpatch-through: 14

Branch
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REL_16_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/391fded1e563692f0ca14b9bd53d33e2e72783a6

Modified Files
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src/backend/utils/adt/tid.c | 7 +++++++
1 file changed, 7 insertions(+)