[InstCombine] canonicalize cmp+select as umin/umax

(V == 0) ? 1 : V --> umax(V, 1)
(V == UMAX) ? UMAX-1 : V --> umin(V, UMAX-1)

https://alive2.llvm.org/ce/z/pfDBAf

This is one pair of the variants discussed in issue #60374.

Enhancements for the other end of the constant range and
signed variants are potential follow-ups, but that may
require more work because we canonicalize at least one
min/max like that to icmp+zext.