[InstCombine] (-NSW x) u<= x --> x s<=0 (PR39480)

Name: (-x) u<= x  -->  x s<= 0
%neg_x = sub nsw i8 0, %x ; %x must not be INT_MIN
%r = icmp ule i8 %neg_x, %x
  =>
%r = icmp sle i8 %x, 0

https://rise4fun.com/Alive/V22

https://bugs.llvm.org/show_bug.cgi?id=39480