Emit future-incompatibility lint when calling/declaring functions with vectors that require missing target feature On some architectures, vector types may have a different ABI depending on whether the relevant target features are enabled. (The ABI when the feature is disabled is often not specified, but LLVM implements some de-facto ABI.) As discussed in https://github.com/rust-lang/lang-team/issues/235, this turns out to very easily lead to unsound code. This commit makes it a post-monomorphization error to declare or call functions using those vector types in a context in which the corresponding target features are disabled, if using an ABI for which the difference is relevant. This ensures that these functions are always called with a consistent ABI. See the [nomination comment](https://github.com/rust-lang/rust/pull/127731#issuecomment-2288558187) for more discussion. r? RalfJung Part of https://github.com/rust-lang/rust/issues/116558