Update to LLVM 22 Scheduled release date: Feb 24 1.94 becomes stable: Mar 5 Changes: * Update to rc2, with one patch to work around our outdated illumos sysroot (https://github.com/rust-lang/llvm-project/commit/41256ab128f2af613b4a16771cda6baa36b55f45). * Update the host toolchain as well, otherwise we lose cross-language LTO, in particular for jemalloc. * Adjust one loongarch assembly test. The split into r and s variants is based on the suggestion in https://github.com/rust-lang/rust/pull/151134. Depends on: * [x] https://github.com/rust-lang/rust/pull/151410 * [ ] https://github.com/rust-lang/rust/issues/150756 * [x] https://github.com/llvm/llvm-project/issues/175190 * [x] https://github.com/llvm/llvm-project/pull/175912 * [x] https://github.com/llvm/llvm-project/issues/175965 * [x] https://github.com/llvm/llvm-project/pull/176195 * [x] https://github.com/llvm/llvm-project/issues/157073 * [x] https://github.com/llvm/llvm-project/issues/176421 * [x] https://github.com/llvm/llvm-project/pull/176925 * [x] https://github.com/llvm/llvm-project/pull/177187