optimization that converts compound selects with ORDER BY COLLATE into subqueries. FossilOrigin-Name: c72324ef9243946550ae3d974826502b1cc5eb10
comparison collations before using the merge algorithm for compound SELECT statements. Candidate fix for ticket [6709574d2a8d8]. FossilOrigin-Name: fc3630cdef6e2cdbfb4e7b373d1a094753e55016