Auto merge of #94214 - nikic:rust-opaque-pointers, r=cuviper

Prepare Rust for opaque pointers

Fix one codegen bug with opaque pointers, and update our IR tests to accept both typed pointer and opaque pointer IR. This is a bit annoying, but unavoidable if we want decent test coverage on both LLVM 14 and LLVM 15.

This prepares Rust for when LLVM will enable opaque pointers by default.

diff --cc src/bootstrap/native.rs
Simple merge