Auto merge of #150722 - nikic:llvm-22, r=cuviper

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 * Update to rc2, with one patch to work around our outdated illumos sysroot (rust-lang/llvm-project@41256ab).
 * 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 rust-lang/rust#151134.

Depends on:

 * [x] rust-lang/rust#151410
 * [ ] rust-lang/rust#150756
 * [x] llvm/llvm-project#175190
 * [x] llvm/llvm-project#175912
 * [x] llvm/llvm-project#175965
 * [x] llvm/llvm-project#176195
 * [x] llvm/llvm-project#157073
 * [x] llvm/llvm-project#176421
 * [x] llvm/llvm-project#176925
 * [x] llvm/llvm-project#177187

Author: bors