Add one null check to tests

Change-Id: Ib4b50ac06d44b1811e0388bc373fe420fa5570fd
diff --git a/tests/src/com/android/launcher3/ui/PortraitLandscapeRunner.java b/tests/src/com/android/launcher3/ui/PortraitLandscapeRunner.java
index ddcb4da..80bb3ed 100644
--- a/tests/src/com/android/launcher3/ui/PortraitLandscapeRunner.java
+++ b/tests/src/com/android/launcher3/ui/PortraitLandscapeRunner.java
@@ -44,8 +44,11 @@
                 } finally {
                     mTest.mDevice.setOrientationNatural();
                     mTest.executeOnLauncher(launcher ->
-                            launcher.getRotationHelper().forceAllowRotationForTesting(
-                                    false));
+                    {
+                        if (launcher != null) {
+                            launcher.getRotationHelper().forceAllowRotationForTesting(false);
+                        }
+                    });
                     mTest.mLauncher.setExpectedRotation(Surface.ROTATION_0);
                 }
             }