added a function to return two dummy types so as to avoid allocating on the ml heap diuring the tree cqual tree walk
added a function to return two dummy types so as to avoid allocating on the ml heap diuring the tree cqual tree walk

samuelhavron/obliv-c,samuelhavron/obliv-c,samuelhavron/obliv-c,samuelhavron/obliv-c