[LV] Add support for minimum/maximum intrinsics

{mini|maxi}mum intrinsics are different from {min|max}num intrinsics in
the propagation of NaN and signed zero. Also, the minnum/maxnum
intrinsics require the presence of nsz flags to be valid reductions in
vectorizer. In this regard, we introduce a new recurrence kind and also
add support for identifying reduction patterns using these intrinsics.

The reduction intrinsics and lowering was introduced here: 26bfbec5.

There are tests added which show how this interacts across chains of
min/max patterns.

Differential Revision: https://reviews.llvm.org/D151482