Remove unused function

Test: atest WMShellFlickerTestsSplitScreen
Change-Id: I55b9d795eb8e0ba7c7a2734d4569fb2bc39dab2c
diff --git a/libs/WindowManager/Shell/tests/flicker/src/com/android/wm/shell/flicker/splitscreen/SplitScreenBase.kt b/libs/WindowManager/Shell/tests/flicker/src/com/android/wm/shell/flicker/splitscreen/SplitScreenBase.kt
index d3434a5..3064bd7 100644
--- a/libs/WindowManager/Shell/tests/flicker/src/com/android/wm/shell/flicker/splitscreen/SplitScreenBase.kt
+++ b/libs/WindowManager/Shell/tests/flicker/src/com/android/wm/shell/flicker/splitscreen/SplitScreenBase.kt
@@ -43,11 +43,4 @@
             secondaryApp.exit(wmHelper)
         }
     }
-
-    protected open val withoutTracing: FlickerBuilder.() -> Unit = {
-        withoutLayerTracing()
-        withoutWindowManagerTracing()
-        withoutTransitionTracing()
-        withoutTransactionsTracing()
-    }
 }