Check that original/linked_list.rs is unchanged

Author: btj

verifast-proofs/check-verifast-proofs.mysh

@@ -3,6 +3,7 @@ cd alloc
     cd linked_list
       verifast -rustc_args "--edition 2021 --cfg test" -skip_specless_fns verified/lib.rs
       refinement-checker --rustc-args "--edition 2021 --cfg test" original/lib.rs verified/lib.rs
+      diff ../../../../library/alloc/src/collections/linked_list.rs original/linked_list.rs
     cd ..
   cd ..
 cd ..