Rollup merge of #59351 - phil-opp:llvm-ar, r=alexcrichton
Rollup merge of #59351 - phil-opp:llvm-ar, r=alexcrichton

Include llvm-ar with llvm-tools component

Adds the `llvm-ar` tool to the `llvm-tools` component. This is useful for [building and linking native code](https://doc.rust-lang.org/cargo/reference/build-scripts.html#case-study-building-some-native-code) in cargo build scripts without needing to use the platform specific `ar`. According to #58663 it is also useful for WASM.

 `llvm-ar` is very small (~82KB), so it does not significantly increase the size of the `llvm-tools` component.

Fixes #58663

aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust