tests: make whitespace between functions and classes consistent

Mostly, this means two blank lines between classes and functions and one
line between methods. Since these checks are currently in preview, they
are done in a separate ruff invocation to avoid turning ALL the preview
checks on at the same time.

tests/http/conftest.py

@@ -148,11 +148,13 @@ def configures_httpd(env, httpd) -> Generator[bool, None, None]:
     # include this fixture as test parameter if the test configures httpd itself
     yield True
 
+
 @pytest.fixture(scope='session')
 def configures_nghttpx(env, httpd) -> Generator[bool, None, None]:
     # include this fixture as test parameter if the test configures nghttpx itself
     yield True
 
+
 @pytest.fixture(autouse=True, scope='function')
 def server_reset(request, env, httpd, nghttpx):
     # make sure httpd is in default configuration when a test starts

tests/http/scorecard.py

@@ -763,7 +763,6 @@ def run_score(args, protocol):
         for x in args.request_parallels:
             request_parallels.extend([int(s) for s in x.split(',')])
 
-
     if args.downloads or args.uploads or args.requests or args.handshakes:
         handshakes = args.handshakes
         if not args.downloads: