Fix the grpc.aio import hack and its unit test

src/python/grpcio/grpc/__init__.py

@@ -2125,6 +2125,6 @@ except ImportError:
     pass
 
 # Prevents import order issue in the case of renamed path.
-if sys.version_info >= (3, 6) and __name__ == "grpc.__init__":
+if sys.version_info >= (3, 6) and __name__ == "grpc":
     from grpc import aio  # pylint: disable=ungrouped-imports
     sys.modules.update({'grpc.aio': aio})

src/python/grpcio_tests/tests_aio/unit/init_test.py

@@ -14,17 +14,15 @@
 import logging
 import unittest
 
-from tests_aio.unit._test_base import AioTestBase
 
+class TestInit(unittest.TestCase):
 
-class TestInit(AioTestBase):
-
-    async def test_grpc(self):
+    def test_grpc(self):
         import grpc  # pylint: disable=wrong-import-position
         channel = grpc.aio.insecure_channel('dummy')
         self.assertIsInstance(channel, grpc.aio.Channel)
 
-    async def test_grpc_dot_aio(self):
+    def test_grpc_dot_aio(self):
         import grpc.aio  # pylint: disable=wrong-import-position
         channel = grpc.aio.insecure_channel('dummy')
         self.assertIsInstance(channel, grpc.aio.Channel)