Remove incorrect validation step for dir targets

The validation in question was comparing directory targets discovered
in the project from directories that are the target of enabled rules
(rules which lack an `enabled_if` field, or whose `enabled_if` condition
is false). This was incorrect as it doesn't account for directory
targets which are the target of disabled rules so the validation fails
if any rule with a directory target is disabled. The validation step was
introduced in 1fd19d7 but there aren't any clues to why it was
necessary.

Fixes ocaml#10310

Signed-off-by: Stephen Sherratt <stephen@sherra.tt>

src/dune_engine/load_rules.ml

@@ -810,35 +810,6 @@ end = struct
       ]
   ;;
 
-  let validate_directory_targets ~dir ~real_directory_targets ~directory_targets =
-    if not
-         (Path.Build.Map.equal real_directory_targets directory_targets ~equal:(fun _ _ ->
-            (* The locations should match if the declaration knows which
-               rule will generate the directory, but it's not necessary
-               as the rule's actual location has higher priority. *)
-            true))
-    then (
-      let mismatched_directories =
-        let error message loc =
-          Dyn.record [ "message", Dyn.string message; "loc", Loc.to_dyn_hum loc ]
-        in
-        Path.Build.Map.merge
-          real_directory_targets
-          directory_targets
-          ~f:(fun _ generated declared ->
-            match generated, declared with
-            | None, None | Some _, Some _ -> None
-            | Some loc, None -> Some (error "not declared" loc)
-            | None, Some loc -> Some (error "not generated" loc))
-      in
-      Code_error.raise
-        "gen_rules returned a set of directory targets that doesn't match the set of \
-         directory targets from returned rules"
-        [ "dir", Path.Build.to_dyn dir
-        ; "mismatched_directories", Path.Build.Map.to_dyn Fun.id mismatched_directories
-        ])
-  ;;
-
   let load_build_directory_exn
     ({ Dir_triage.Build_directory.dir; context_name; context_type; sub_dir } as build_dir)
     =
@@ -893,10 +864,6 @@ end = struct
         descendants_to_keep build_dir build_dir_only_sub_dirs ~source_dirs rules_produced
       in
       let rules_here = compile_rules ~dir ~source_dirs rules in
-      validate_directory_targets
-        ~dir
-        ~real_directory_targets:(Rules.directory_targets rules_produced)
-        ~directory_targets;
       (let subdirs_to_keep = Subdir_set.of_dir_set descendants_to_keep in
        remove_old_artifacts ~dir ~rules_here ~subdirs_to_keep;
        remove_old_sub_dirs_in_anonymous_actions_dir

test/blackbox-tests/test-cases/disable-rule-with-directory-target.t

@@ -0,0 +1,15 @@
+
+
+  $ cat > dune-project <<EOF
+  > (lang dune 3.14)
+  > (using directory-targets 0.1)
+  > EOF
+
+  $ cat > dune <<EOF
+  > (rule
+  >  (enabled_if false)
+  >  (target (dir x))
+  >  (action (run mkdir x)))
+  > EOF
+
+  $ dune build