[InstCombine] Add foldAndOfICmps test cases inspired by PR42691.

icmp ne %x, INT_MIN can be treated similarly to icmp sgt %x, INT_MIN.
icmp ne %x, INT_MAX can be treated similarly to icmp slt %x, INT_MAX.
icmp ne %x, UINT_MAX can be treated similarly to icmp ult %x, UINT_MAX.

We already treat icmp ne %x, 0 similarly to icmp ugt %x, 0

llvm-svn: 366662