[clang] [AArch64][SME] Warn when using a streaming builtin from a non-streaming function (PR #75487)

[Sam Tebbs via cfe-commits]

SamTebbs33 wrote:

> If it's not too much trouble, could you `git cherry-pick c60663d128f8e0dccd418bdf16ecc403b96aa74a` into this? (Cool if not, ofc.)

Sure, I can do that. Would you also mind attempting to reproduce the compile time with the latest commit, just to make sure it fixes the issue on your end? I saw a 36 -> 31 second (compared to 30 on main) decrease which seems OK but isn't on the same scale as the numbers you're seeing.

https://github.com/llvm/llvm-project/pull/75487