[AArch64][SVE] Implement floating-point comparison & reduction intrinsics

Summary:
Adds intrinsics for the following:
 - fadda & faddv
 - fminv, fmaxv, fminnmv & fmaxnmv
 - facge & facgt
 - fcmp[eq|ge|gt|ne|uo]

Reviewers: sdesmalen, huntergr, dancgr, mgudim

Reviewed By: sdesmalen

Subscribers: tschuett, kristof.beyls, hiraditya, rkruppe, psnobl, cameron.mcinally, cfe-commits, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69858