[clang] [llvm] [LLVM] Respect `optnone` in `promote-args` and `deadargelim` (PR #211804)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> Rather than adding a new helper that is only checked in 20% of the necessary places, can you hook this into isInterposable() similar to the noipa handling?

Done, doing it this way had some collateral damage with devirtualization tests, I'm assuming it's an acceptable tradeoff, if not I can maintain the old behavior explicitly.

https://github.com/llvm/llvm-project/pull/211804