Extend SubstitutionVisitor.splitFilter to cover different order of operands

SubstitutionVisitor.splitFilter does structural comparison to identify relevant predicates. The method could sort the operands for some expressions in a deterministic way to maximize possible matches.

For instance, currently this example yields correct results:

condition: x = 1 or y = 2
target:    y = 2 or x = 1
-> residue:   true

However, the following equivalent example fails:

condition: x = 1 or y = 2
target:    y = 2 or 1 = x