pgsql: Add test for logical decoding with an oid8 TOAST table and OID >

Add test for logical decoding with an oid8 TOAST table and OID > 2^32

The test_decoding tests would usually run with an OID counter way below
the UINT32_MAX limit, meaning that any toast value handled would always
fit in 4 bytes.

This commit adds a short test based on an oid8 TOAST table and an OID
past 2^32, forcing an overflow check of the logical replication code
when dealing with the detoasting of externally TOASTed values.

Author: Rui Zhao <zhaorui126(at)gmail(dot)com>
Discussion: https://postgr.es/m/aqd_gYs35v--sVlR@paquier.xyz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/a3f4fc5bacc8c4868ad6b5a02a65cbb4c0846c01

Modified Files
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src/test/recovery/t/006_logical_decoding.pl | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)