unittest: TestCase: Add (dummy) __init__.

Mostly to workaround inherited MicroPython's issues with inheritance.

Signed-off-by: Paul Sokolovsky <[email protected]>

Author: pfalcon

python-stdlib/unittest/unittest.py

@@ -30,6 +30,9 @@ def __exit__(self, exc_type, exc_value, tb):
 
 
 class TestCase:
+    def __init__(self):
+        pass
+
     def fail(self, msg=""):
         assert False, msg