Cleaning up AArch64Sem.ml (in relation to the bugfixes)

Removing a comment. Removing a bit of logic preparing a list of
overwriting instructions: currently instructions loaded from the initial
state are a superset of what gets loaded from code, therefore, removing
the latter.

herd/AArch64Sem.ml

@@ -2701,19 +2701,15 @@ module Make
  * overwrite another. By convention, those are
  * instructions pointed to by "exported" labels.
  *)
-      let get_overwriting_instrs lbls test =
+      let get_overwriting_instrs test =
         let init_instrs =
           AArch64.state_fold
             (fun _ v k ->
               match v with
               | V.Val (Constant.Instruction i) -> i::k
               | _ -> k)
-            test.Test_herd.init_state []
-        and  code_instrs =
-          List.map
-            (fun (_,i) -> i)
-            (AArch64.from_labels lbls test.Test_herd.nice_prog) in
-        init_instrs@code_instrs
+            test.Test_herd.init_state [] in
+        init_instrs
 
 
 (* Test all possible instructions, when appropriate *)
@@ -2734,15 +2730,9 @@ module Make
           | Some hd ->
               let insts =
                 InstrSet.of_list
-                  (get_overwriting_instrs lbls test) in
+                  (get_overwriting_instrs test) in
               let insts =
                 InstrSet.add inst (InstrSet.filter AArch64.can_overwrite insts) in
-              if false then
-                Printf.eprintf "%s: {%s}\n%!"
-                  (Label.pp hd)
-                  (String.concat ","
-                      (List.map AArch64.V.Cst.Instr.pp
-                        (InstrSet.elements insts))) ;
               (* Shadow default control sequencing operator *)
               let(>>*=) = M.bind_control_set_data_input_first in
               let a_v = make_label_value ii.A.fetch_proc hd in