Auto merge of #113343 - saethlin:looser-alignment, r=RalfJung

Update the alignment checks to match rust-lang/reference#1387

Previously, we had a special case to not check `Rvalue::AddressOf` in this pass because we weren't quite sure if pointers needed to be aligned in the Place passed to it: rust-lang/rust#112026

Since rust-lang/reference#1387 merged, this PR updates this pass to match. The behavior of the check is nearly unchanged, except we also avoid inserting a check for creating references. Most of the changes in this PR are cleanup and new tests.

Author: bors