Don't ignore a duplicate host for an already processed include (#40361)

* Don't ignore a duplicate host for an already processed include, assume that the repetition indicates a new include. Fixes #40317

* Add intg tests to ensure duplicate items in loop are not deduped

* Add note about relative indexing

test/integration/targets/include_import/runme.sh

@@ -73,3 +73,9 @@ if [[ -z "$OUT" ]]; then
     echo "apply on import_tasks did not cause error"
     exit 1
 fi
+
+# Test that duplicate items in loop are not deduped
+ANSIBLE_STRATEGY='linear' ansible-playbook tasks/test_include_dupe_loop.yml -i ../../inventory "$@" | tee test_include_dupe_loop.out
+test "$(grep -c 'item=foo' test_include_dupe_loop.out)" = 3
+ANSIBLE_STRATEGY='free' ansible-playbook tasks/test_include_dupe_loop.yml -i ../../inventory "$@" | tee test_include_dupe_loop.out
+test "$(grep -c 'item=foo' test_include_dupe_loop.out)" = 3

test/integration/targets/include_import/tasks/debug_item.yml

@@ -0,0 +1,2 @@
+- debug:
+    msg: "item={{ item }}"

test/integration/targets/include_import/tasks/test_include_dupe_loop.yml

@@ -0,0 +1,8 @@
+- name: Test Include Duplicate Loop Items
+  hosts: testhost
+  tasks:
+    - include_tasks: debug_item.yml
+      loop:
+        - foo
+        - foo
+        - foo