Make sure to teardown MockConnectionService if previously injected

Fix flakiness in other tests

Bug: 20303674
Change-Id: I9298d189c6a2467817fa894b3ea79ffe5f45f6af
diff --git a/tests/tests/telecom/src/android/telecom/cts/SimpleTelecomTest.java b/tests/tests/telecom/src/android/telecom/cts/SimpleTelecomTest.java
index 13799ae..377a999 100644
--- a/tests/tests/telecom/src/android/telecom/cts/SimpleTelecomTest.java
+++ b/tests/tests/telecom/src/android/telecom/cts/SimpleTelecomTest.java
@@ -51,6 +51,7 @@
 
     @Override
     protected void tearDown() throws Exception {
+        MockConnectionService.tearDown();
         super.tearDown();
     }