Issue #20505: Fix TestLoop, set the clock resolution
diff --git a/Lib/asyncio/test_utils.py b/Lib/asyncio/test_utils.py
index 71d69cf..7c8e1dc 100644
--- a/Lib/asyncio/test_utils.py
+++ b/Lib/asyncio/test_utils.py
@@ -191,6 +191,7 @@
         self._gen = gen()
         next(self._gen)
         self._time = 0
+        self._clock_resolution = 1e-9
         self._timers = []
         self._selector = TestSelector()