Rust: restore toolchain 2025-05-12 (#79121)
This restores #79117.
https://github.com/rust-lang/rust/issues/71520 broke Windows on arm64
when using rust-lld, so this disables that for now.
Test Plan: `pnpm --filter=@next/swc run build-native-no-plugin-release
--target aarch64-pc-windows-msvc` on Windows on arm64.
