removing incorrect validation check; it turns out that there is legitimate (although odd) Java code that can cause self-loops; see this test case from abc:

    static int m1(boolean t) {
    loop: while (true) {
        if (t) break loop;
    }
    return 1;
    }
Merge commit '957cc8c650d3d7e918d9cf41a9bb3dc380dfe193' into develop