pgsql: Fix test_rls_hooks to assign expression collations properly.

Fix test_rls_hooks to assign expression collations properly.

This module overlooked this necessary fixup step on the results of
transformWhereClause().  It accidentally worked anyway, because the
constructed expression involved type "name" which is not collatable,
but it fell over while I was experimenting with changing "name" to
be collatable.

Back-patch, not because there's any live bug here in back branches,
but because somebody might use this code as a model for some real
application and then not understand why it doesn't work.

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/4e33da5f0af340da40bd51354b87332c551a4bbc

Modified Files
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src/test/modules/test_rls_hooks/test_rls_hooks.c | 5 +++++
1 file changed, 5 insertions(+)