DESCRIPTION: Fix regression in allowed foreign keys on distributed
tables
In commit eadc88a we changed how we skip foreign key validation. The
goal was to skip it in more cases. However, one change had the
unintended regression of introducing failures when trying to create
certain foreign keys. This reverts that part of the change.
The way of skipping validation of foreign keys that was introduced in
eadc88a was skipping validation during execution. The reason that
this caused this regression was because some foreign key validation
queries already fail during planning. In those cases it never gets to
the execution step where it would later be skipped.
Fixes#6543
Jelte Fennema