pgsql: Partially restore qual scope checks in distribute_qual_to_rels()

Partially restore qual scope checks in distribute_qual_to_rels().

The LATERAL implementation is now basically complete, and I still don't
see a cost-effective way to make an exact qual scope cross-check in the
presence of LATERAL.  However, I did add a PlannerInfo.hasLateralRTEs flag
along the way, so it's easy to make the check only when not hasLateralRTEs.
That seems to still be useful, and it beats having no check at all.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/c97a547a4a0913e37e5dd1f026ac3c281326b215

Modified Files
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src/backend/optimizer/plan/initsplan.c |   28 +++++++++++++---------------
1 files changed, 13 insertions(+), 15 deletions(-)