Rustc updated to LLVM 17, for ~2% compile time improvements

The Rust compiler has updated to LLVM 17, which resulted in nice compile-time wins (https://perf.rust-lang.org/compare.html?start=03a119b0b0e310d22d94399b24ed030056050f13&end=443c3161dd04f4c1b656a626f9079921bee9c326&stat=instructions%3Au&tab=compile&nonRelevant=true). It seems that code generation quality was also improved if we are to believe the newly introduced runtime benchmarks :)

The corresponding PR is here:
https://github.com/rust-lang/rust/pull/114048