Expand complex predicates into simpler conditional, then mutate

[dkubb]

One thing I've found when specifying compound statements like foo <= bar is that to test it properly, I need to expand it into foo < bar || foo == bar, then mutate that statement. Simply changing the sign does not expose all possible mutations.

It would be nice for mutant to expand those statements first, then mutate the expanded expression.

[mbj]

I like this mutation. We could first emit the mutation from: foo <= bar to foo < bar || foo == bar as neutral mutation, and then the mutations of the expansion as evil ones.