* nxos_vlan: fix broken purge behavior (issue #57101)
Symptoms/Analysis:
- `nxos_vlan` `purge: true` would fail when `purge` was trying to delete all unspecified vlans, including vlan 1.
- `nxos` devices do not allow removing vlan 1 and raise a cli exception error
- Previous fix#55144 caused a side effect when `purge` was used: vlan changes specified by `aggregate` were ignored; e.g.
- vlan 4 is not present; playbook specifies `aggregate: { vlan: 4 }, purge: true`
- results in proper purging but vlan 4 is not created
Solutions:
- ignore vlan 1 when purging
- remove the `not purge` check from state present logic
Added additional unit tests and integration tests.
Tested against all regression platforms.
* PEP fixes
* Add agg_show_vlan_brief.txt fixture
* Add warning for removing vlan 1
* change method name check
* Move ansible.compat.tests to test/units/compat/.
* Fix unit test references to ansible.compat.tests.
* Move builtins compat to separate file.
* Fix classification of test/units/compat/ dir.
* move set_module_args to units.modules.utils
* unit tests: reuse set_module_args
* unit tests: mock exit/fail_json in module.utils.ModuleTestCase
* unit tests: use module.utils.ModuleTestCase
* unit tests: fix 'import shadowed by loop variable'
* Extend tests to have multiple device representations
* Move filepath munging to nxos_module
* Device needs to be kwarg so we can leave it off
* Update other nxos tests
* Update tests that fell through
