Avoid duplicate type sanitization of local decls

The type of the local decl is already sanitized in `visit_local_decl`.

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -477,9 +477,7 @@ fn visit_local_decl(&mut self, local: Local, local_decl: &LocalDecl<'tcx>) {
 
     fn visit_body(&mut self, body: &Body<'tcx>) {
         self.sanitize_type(&"return type", body.return_ty());
-        for local_decl in &body.local_decls {
-            self.sanitize_type(local_decl, local_decl.ty);
-        }
+        // The types of local_decls are checked above which is called in super_body.
         self.super_body(body);
     }
 }