Big simplification of get_loop_info
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.