Adding TaplTestsSplitscreen to OOP tests

It's a nice addition to our OOP tests, which serve as a kind-of ssmoke check for the system, as well a a test for a proguarded Launcher.

Bug: 187761685
Flag: N/A
Test: presubmit

Change-Id: I196cf0047f0df6cf843615e48252035f216597a0
diff --git a/quickstep/Android.bp b/quickstep/Android.bp
index f5a8253..638ce27 100644
--- a/quickstep/Android.bp
+++ b/quickstep/Android.bp
@@ -42,5 +42,6 @@
         "tests/src/com/android/quickstep/NavigationModeSwitchRule.java",
         "tests/src/com/android/quickstep/AbstractQuickStepTest.java",
         "tests/src/com/android/quickstep/TaplTestsQuickstep.java",
+        "tests/src/com/android/quickstep/TaplTestsSplitscreen.java",
     ]
 }