Avoid 2nd processing of facts for actions

[bcoca]

SUMMARY

include_vars and set_fact are already updating hostvars in strategy
no need to 're add again' with lower priority the same data.

fixes #37535, mostly by avoiding reprocessing and 'cleaning'

ISSUE TYPE

• Bugfix Pull Request

COMPONENT NAME

facts

ANSIBLE VERSION

2.5/2.6

[nitzmahone]

cherry-picked to stable-2.5 for 2.5.1

[NomAnor]

This breaks the following playbook which should output the array ['one', ..., 'four'] instead it outputs ['one', 'four'].

---
- name: test set_fact bug
  hosts: localhost
  connection: local
  gather_facts: no
  vars:
    - dig_list:
      - one

    - digits:
      - two
      - three
      - four
  tasks:

    - name: test bug
      set_fact:
        dig_list: "{{ dig_list + [ digit ] }}"
      with_items: "{{ digits }}"
      loop_control:
        loop_var: digit

    - debug: msg="{{ dig_list }}"

See also #23624. This breaks one of my roles.