[llvm] [AArch64] Avoid inlining if ZT0 needs preserving. (PR #101343)

[Paul Walker via llvm-commits]

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

Is it worth testing the other zt0 attributes? I ask not because of an issue with this patch, which looks fine to my eye, but because I'm less sure `requiresPreservingZT0` is valid.  That said, this function is new to me so perhaps I've misunderstood.

For the case where the caller is `aarch64_inout_zt0` or `aarch64_in_zt0` should zt0 be preserved when calling a `aarch64_out_zt0` function? `requiresPreservingZT0` suggests not?

https://github.com/llvm/llvm-project/pull/101343