Another remnant of trying to devise a complicated algorithm for a
problem that was, in fact, very simple: I just had to check whether the
branch was within the loop body.

I tested it functionally on the benchmarks: only heapsort is changed, in
slightly worst (4-5%), because the old get_loop_info had done a buggy
guess that proved to be lucky for that particular case.

The other benchmarks are unchanged: the predictions stay the exact same.

The get_loop_info could potentially be improved by having a natural loop
detection that extends to outer loops (not just inner loops), though I
expect the performance improvements would be very small.