Deprecation and test cleanup (#1818)

* Remove remove_route, deprecated in 19.6.

* No need for py35 compat anymore.

* Rewrite asyncio.coroutines with async/await.

* Remove deprecated request.raw_args.

* response.text() takes str only: avoid deprecation warning in all but one test.

* Remove unused import.

* Revert unnecessary deprecation warning.

* Remove apparently unnecessary py38 compat.

* Avoid asyncio.Task.all_tasks deprecation warning.

* Avoid warning on a test that tests deprecated response.text(int).

* Add pytest-asyncio to tox deps.

* Run the coroutine returned by AsyncioServer.close.

Co-authored-by: L. Kärkkäinen <tronic@users.noreply.github.com>

tests/test_requests.py

@@ -1607,33 +1607,6 @@ async def test_request_args_no_query_string_await(app):
     assert request.args == {}
 
 
-def test_request_raw_args(app):
-
-    params = {"test": "OK"}
-
-    @app.get("/")
-    def handler(request):
-        return text("pass")
-
-    request, response = app.test_client.get("/", params=params)
-
-    assert request.raw_args == params
-
-
-@pytest.mark.asyncio
-async def test_request_raw_args_asgi(app):
-
-    params = {"test": "OK"}
-
-    @app.get("/")
-    def handler(request):
-        return text("pass")
-
-    request, response = await app.asgi_client.get("/", params=params)
-
-    assert request.raw_args == params
-
-
 def test_request_query_args(app):
     # test multiple params with the same key
     params = [("test", "value1"), ("test", "value2")]