Ensure exit_json returns failed = False

This is required for modules that may return a non-zero `rc` value for a
successful run, similar to #24865 for Windows fixing **win_chocolatey**.

We also disable the dependency on `rc` value only, even if `failed` was
set.

Adapted unit and integration tests to the new scheme.
Updated raw, shell, script, expect to take `rc` into account.

test/integration/targets/ec2_group/tasks/main.yml

@@ -188,11 +188,6 @@
         state=absent
       register: result
 
-    - name: assert state=absent
-      assert:
-        that:
-           - '"failed" not in result'
-
     # ============================================================
     - name: test state=present (expected changed=true)
       ec2_group: