Non-tuple exact and in lookups have specialized logic for subqueries that can
be adapted to properly assign select mask if unspecified and ensure the number
of involved members are matching on both side of the operator.
Backport of 41239fe34d64e801212dccaa4585e4802d0fac68 from main.
Thanks Lily Foote and Simon Charette for reviews and mentoring
this Google Summer of Code 2024 project.
Co-authored-by: Simon Charette <charette.s@gmail.com>
Co-authored-by: Lily Foote <code@lilyf.org>