Revert "Added mockito-extended support to WmTests."

This reverts commit 953fd225ccba3f46e336228362063bcafcac7fd5.

Reason for revert: Breaks pre-submit tests in cloud...
Bug: 113806960

Change-Id: I464d6a3acd40bfb112d94cbc4ff1c076ba5b59f1
diff --git a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
index 30eb500..1d00075 100644
--- a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
+++ b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
@@ -341,8 +341,7 @@
     ActivityManagerInternal mAmInternal;
     UriGrantsManagerInternal mUgmInternal;
     private PackageManagerInternal mPmInternal;
-    @VisibleForTesting
-    final ActivityTaskManagerInternal mInternal;
+    private ActivityTaskManagerInternal mInternal;
     PowerManagerInternal mPowerManagerInternal;
     private UsageStatsManagerInternal mUsageStatsInternal;
 
@@ -644,7 +643,6 @@
         mSystemThread = ActivityThread.currentActivityThread();
         mUiContext = mSystemThread.getSystemUiContext();
         mLifecycleManager = new ClientLifecycleManager();
-        mInternal = new LocalService();
         GL_ES_VERSION = SystemProperties.getInt("ro.opengles.version", GL_ES_VERSION_UNDEFINED);
     }
 
@@ -895,6 +893,7 @@
     }
 
     private void start() {
+        mInternal = new LocalService();
         LocalServices.addService(ActivityTaskManagerInternal.class, mInternal);
     }
 
@@ -6871,4 +6870,4 @@
             }
         }
     }
-}
+}
\ No newline at end of file