Add @VisibleForTest to TestLoaderManager ctor

Fix for some old test failures inside
ContactDeletionInteractionTest.

Change-Id: I7b61f9d7749d82b148d0600e671904c3cc0fc865
diff --git a/src/com/android/contacts/interactions/TestLoaderManager.java b/src/com/android/contacts/interactions/TestLoaderManager.java
index fb6a49b..a85bf8f 100644
--- a/src/com/android/contacts/interactions/TestLoaderManager.java
+++ b/src/com/android/contacts/interactions/TestLoaderManager.java
@@ -93,6 +93,7 @@
 
     private LoaderManager mDelegate;
 
+    @VisibleForTesting
     public TestLoaderManager() {
         mFinishedLoaders = new HashSet<Integer>();
     }