[issue38107] Replace direct future and task contructor calls with factories in asyncio tests

[miss-islington]

Change by miss-islington <mariatta.wijaya+miss-islington at gmail.com>:


----------
pull_requests: +15573
pull_request: https://github.com/python/cpython/pull/15937

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue38107>
_______________________________________