[llvm] [AArch64] Consider runtime mode when deciding to use SVE for fixed-length vectors. (PR #96081)

[Paul Walker via llvm-commits]

https://github.com/paulwalker-arm commented:

I'm guessing there's another PR to change the scalable vector specific instances of `hasSVEorSME()`?

https://github.com/llvm/llvm-project/pull/96081