Move methods from Map to TyCtxt, part 4.

Continuing the work from #137350.

Removes the unused methods: `expect_variant`, `expect_field`,
`expect_foreign_item`.

Every method gains a `hir_` prefix.

compiler/rustc_codegen_ssa/src/assert_module_sources.rs

@@ -63,7 +63,7 @@ pub fn assert_module_sources(tcx: TyCtxt<'_>, set_reuse: &dyn Fn(&mut CguReuseTr
             },
         };
 
-        for attr in tcx.hir().attrs(rustc_hir::CRATE_HIR_ID) {
+        for attr in tcx.hir_attrs(rustc_hir::CRATE_HIR_ID) {
             ams.check_attr(attr);
         }