Revert "Enable @PortraitLandscape for testBackground"

This reverts commit b6e2cd8546.

Reason for revert: b/135567630

Change-Id: I4cd87356177a141c99e3865b8794de58386d0f49

quickstep/tests/src/com/android/quickstep/TaplTestsQuickstep.java

@@ -208,7 +208,7 @@ public class TaplTestsQuickstep extends AbstractQuickStepTest {
 
     @Test
     @NavigationModeSwitch
-    @PortraitLandscape
+//    @PortraitLandscape
     public void testBackground() throws Exception {
         startAppFast(resolveSystemApp(Intent.CATEGORY_APP_CALCULATOR));
         final Background background = mLauncher.getBackground();