[llvm] [AArch64] Disable consecutive store merging when Neon is unavailable (PR #111519)

[Benjamin Maxwell via llvm-commits]

MacDue wrote:

Note: See https://github.com/llvm/llvm-project/pull/111519/commits/321290a49d409620a8072f5bd8d8f917b215d09f for the difference between the precommit and with these changes. 

https://github.com/llvm/llvm-project/pull/111519