Fix i1 vector reduction miscompilation

Previously, `vecreduce_{and,or} vNi1` could lead to miscompilations because the legalizer first decides to `any_ext` the operand (which is correct for `vecreduce_{and,or}`) and then decides to use `vecreduce_u{min,max}` instead (for which `any_ext` is incorrect). This patch changes it so the `vecreduce_u{min,max}` operations use `sign_ext` instead of `any_ext`.

Issue: https://github.com/llvm/llvm-project/issues/62211

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D148672