PY-23785: support unittest2, PY-23846: support dots in subtest names

Leonid's runners updated to support unittest2 and  dots in subtests

python/testData/testRunner/env/unit/subtestDots/test_test.py

@@ -0,0 +1,9 @@
+import unittest
+
+
+class SampleTest(unittest.TestCase):
+
+    def test_sample(self):
+        for i in range(10):
+            with self.subTest(i=str(i)+'.'+str(i)):
+                self.assertTrue(i > 1)

python/testData/testRunner/env/unit/unittest2/test_test.py

@@ -0,0 +1,10 @@
+
+from unittest2 import TestCase
+
+
+class SampleTest(TestCase):
+
+    def test_sample(self):
+        for i in range(10):
+            with self.subTest(i=i):
+                self.assertTrue(i > 3)