[Telemetry] discover.DiscoverClasses() does not add inherited classes.

tools/telemetry/telemetry/core/discover_unittest.py

Index: tools/telemetry/telemetry/core/discover_unittest.py
diff --git a/tools/telemetry/telemetry/core/discover_unittest.py b/tools/telemetry/telemetry/core/discover_unittest.py
index dda14a360efa06cc1212f76d73e6cc764578d078..9fa0c1187d15a0ec148275ec21e90432821abc78 100644
--- a/tools/telemetry/telemetry/core/discover_unittest.py
+++ b/tools/telemetry/telemetry/core/discover_unittest.py
@@ -14,11 +14,10 @@ class DiscoverTest(unittest.TestCase):
     base_class = Exception
     classes = discover.DiscoverClasses(start_dir, base_dir, base_class)
     self.assertTrue(len(classes) > 0)
-
-    found_dummy_exception = False
     for c in classes.values():
-      if c.__name__ == 'DummyException':
-        found_dummy_exception = True
       self.assertTrue(issubclass(c, Exception))
 
-    self.assertTrue(found_dummy_exception)
+    # discover_dummyclass is a base class and should not show up.
+    self.assertFalse('discover_dummyclass' in classes)
+    self.assertEqual(classes['another_discover_dummyclass'].__name__,
+                     'AnotherDummyException')