Auto merge of #133883 - saethlin:remove-polymorphization, r=compiler-errors

Remove polymorphization

This PR removes the flag `-Zpolymorphize` and all the infrastructure in the compiler that exists only to support it, per rust-lang/compiler-team#810.

Author: bors

crates/hir-expand/src/inert_attr_macro.rs

@@ -695,7 +695,6 @@ pub const INERT_ATTRIBUTES: &[BuiltinAttribute] = &[
         template!(List: r#"cfg = "...", module = "...", kind = "...""#), DuplicatesOk,
     ),
     rustc_attr!(TEST, rustc_symbol_name, Normal, template!(Word), WarnFollowing),
-    rustc_attr!(TEST, rustc_polymorphize_error, Normal, template!(Word), WarnFollowing),
     rustc_attr!(TEST, rustc_def_path, Normal, template!(Word), WarnFollowing),
     rustc_attr!(TEST, rustc_mir, Normal, template!(List: "arg1, arg2, ..."), DuplicatesOk),
     gated!(