asyncio: Initialize more Future and Task attributes in the class definition to
avoid attribute errors in destructors.
Issue #22685: Fix test_pause_reading() of asyncio test_subprocess

* mock also resume_reading()
* ensure that resume_reading() is called
Closes #22922: More EventLoop methods fail if the loop is closed. Initial patch
written by Torsten Landschoff.

create_task(), call_at(), call_soon(), call_soon_threadsafe() and
run_in_executor() now raise an error if the event loop is closed.
Merge 3.4 (asyncio)