Re-organize directory structure (#4971)

See discussion in #2491

Co-authored-by: Ivan Levkivskyi <ilevkivskyi@dropbox.com>

stdlib/unittest/runner.pyi

@@ -0,0 +1,35 @@
+import unittest.case
+import unittest.result
+import unittest.suite
+from typing import Callable, Optional, TextIO, Tuple, Type, Union
+
+_ResultClassType = Callable[[TextIO, bool, int], unittest.result.TestResult]
+
+class TextTestResult(unittest.result.TestResult):
+    descriptions: bool  # undocumented
+    dots: bool  # undocumented
+    separator1: str
+    separator2: str
+    showall: bool  # undocumented
+    stream: TextIO  # undocumented
+    def __init__(self, stream: TextIO, descriptions: bool, verbosity: int) -> None: ...
+    def getDescription(self, test: unittest.case.TestCase) -> str: ...
+    def printErrors(self) -> None: ...
+    def printErrorList(self, flavour: str, errors: Tuple[unittest.case.TestCase, str]) -> None: ...
+
+class TextTestRunner(object):
+    resultclass: _ResultClassType
+    def __init__(
+        self,
+        stream: Optional[TextIO] = ...,
+        descriptions: bool = ...,
+        verbosity: int = ...,
+        failfast: bool = ...,
+        buffer: bool = ...,
+        resultclass: Optional[_ResultClassType] = ...,
+        warnings: Optional[Type[Warning]] = ...,
+        *,
+        tb_locals: bool = ...,
+    ) -> None: ...
+    def _makeResult(self) -> unittest.result.TestResult: ...
+    def run(self, test: Union[unittest.suite.TestSuite, unittest.case.TestCase]) -> unittest.result.TestResult: ...