[AArch64][SVE] Replace integer immediate intrinsics with splat vector variant
Summary: Replace the integer immediate intrisics with splat vector variants so they can be applied as optimizations for the C/C++ intrinsics.
Reviewers: sdesmalen, huntergr, rengolin, efriedma, c-rhodes, mgudim, kmclaughlin
Subscribers: tschuett, kristof.beyls, hiraditya, rkruppe, psnobl, llvm-commits, amehsan
Differential Revision: https://reviews.llvm.org/D71614