IdenticalLink fails to find all permutations.

[linas]

This is demonstrated in https://github.com/opencog/atomspace/tree/master/tests/query/unify-test.scm lines 197 ff

The actual and the expected results don't match. My guess of where the bug is, is that its in the static analysis of IdenticalLink. Basically, IdenticalLink tries to do a static analysis, which, if its possible, avoid the need for a dynamic run of the query engine. But this static analysis is relatively minimal, kind-of dumb. And my guess is that it failed to notice that it's dealing with an unordered link. I think that's where the bug is. But it could be somewhere else ...