[AArch64] Add SVE lowering for vector.reduce.fminimum and fmaximum

Following what is already performed for vector.reduce.fmin/fmax, this adds
lowering for the new vector.reduce.fminimum/fmaximum nodes to the SVE fminv
and fmaxv instructions via the existing FMINV_PRED/FMAXV_PRED nodes.

Differential Revision: https://reviews.llvm.org/D153288