Rollup merge of #124876 - nnethercote:rm-use-crate-rustc_foo, r=compiler-errors

Simplify `use crate::rustc_foo::bar` occurrences.

They can just be written as `use rustc_foo::bar`, which is far more standard. (I didn't even know that a `crate::` prefix was valid.)

r? ``@eholk``

Author: matthiaskrgr

src/shims/x86/avx2.rs

@@ -1,5 +1,5 @@
-use crate::rustc_middle::ty::layout::LayoutOf as _;
 use rustc_middle::mir;
+use rustc_middle::ty::layout::LayoutOf as _;
 use rustc_middle::ty::Ty;
 use rustc_span::Symbol;
 use rustc_target::spec::abi::Abi;