application: Remove preliminary argument parsing state

The preliminary options and arguments returned from
`.parse_preliminary_options_and_args()` are now all threaded through to
the appropriate methods during initialization.

src/flake8/main/application.py

@@ -51,11 +51,6 @@ class Application(object):
             prog="flake8", version=flake8.__version__
         )
         options.register_default_options(self.option_manager)
-        #: The preliminary options parsed from CLI before plugins are loaded,
-        #: into a :class:`argparse.Namespace` instance
-        self.prelim_opts = None  # type: argparse.Namespace
-        #: The preliminary arguments parsed from CLI before plugins are loaded
-        self.prelim_args = None  # type: List[str]
         #: The instance of :class:`flake8.options.config.ConfigFileFinder`
         self.config_finder = None  # type: config.ConfigFileFinder
 
@@ -108,8 +103,6 @@ class Application(object):
         options; we ignore those for now, they'll be parsed later when we do
         real option parsing.
 
-        Sets self.prelim_opts and self.prelim_args.
-
         :param list argv:
             Command-line arguments passed in directly.
         :returns:
@@ -142,7 +135,6 @@ class Application(object):
         opts, args = self.option_manager.parse_known_args(args)
         # parse_known_args includes unknown options as args
         args = [a for a in args if not a.startswith("-")]
-        self.prelim_opts, self.prelim_args = opts, args
         return opts, args
 
     def exit(self):

tests/unit/test_application.py

@@ -95,12 +95,9 @@ def test_prelim_opts_args(application):
     opts, args = application.parse_preliminary_options_and_args(
         ['flake8', '--foo', '--verbose', 'src', 'setup.py', '--statistics'])
 
-    assert application.prelim_opts.statistics
-    assert application.prelim_opts.verbose
-    assert application.prelim_args == ['src', 'setup.py']
-    assert opts.statistics is application.prelim_opts.statistics
-    assert opts.verbose is application.prelim_opts.verbose
-    assert args is application.prelim_args
+    assert opts.statistics
+    assert opts.verbose
+    assert args == ['src', 'setup.py']
 
 
 def test_prelim_opts_handles_empty(application):
@@ -109,5 +106,4 @@ def test_prelim_opts_handles_empty(application):
     with mock.patch.object(sys, 'argv', irrelevant_args):
         opts, args = application.parse_preliminary_options_and_args([])
 
-        assert application.prelim_args == []
-        assert args is application.prelim_args
+        assert args == []

tests/unit/test_legacy_api.py

@@ -18,7 +18,6 @@ def test_get_style_guide():
         verbose=0,
     )
     mockedapp = mock.Mock()
-    mockedapp.prelim_opts = prelim_opts
     mockedapp.parse_preliminary_options_and_args.return_value = (
         prelim_opts,
         [],