[llvm] [AArch64] Set the default streaming hazard size to 1024 for +sme,+sve (PR #123753)

[Amara Emerson via llvm-commits]

aemerson wrote:

@sdesmalen-arm @MacDue I don't understand why this was done. This is a micro-architecture specific optimization and I think it's useful, but it should be a CPU feature opt-in rather than a default value of 1k (why 1k? why not 4k to at least be a small page size?).

It also unnecessarily adds noise to test RUN lines.

https://github.com/llvm/llvm-project/pull/123753