[AArch64][SVEIntrinsicOpts] Fix: predicated SVE mul/fmul are not commutative

We can not swap multiplicand and multiplier because the sve intrinsics
are predicated. Imagine lanes in vectors having the following values:
         pg = 0
         multiplicand = 1 (from dup)
         multiplier = 2
The resulting value should be 1, but if we swap multiplicand and multiplier it will become 2,
which is incorrect.

Differential Revision: https://reviews.llvm.org/D114577