[AArch64][InstCombine] Fuse ADD+MUL and SUB+MUL AArch64 instrinsics

Fold (ADD p c (MUL p a b)) into (MAD p a b c)
Fold (FADD p c (FMUL p a b)) into (FMAD p a b c)
Fold (FSUB p c (FMUL p a b)) into (FNMSB p a b c)

Fold (ADD p (MUL p a b) c) into (MLA p c a b)
Fold (FADD p (FMUL p a b) c) into (FMLA p c a b)
Fold (SUB p (MUL p a b) C) into (MLS p c a b)
Fold (FSUB p (FMUL p a b) c) into (FMLS p c a b)

Differential Revision: https://reviews.llvm.org/D140200