* 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'
