Launch SplitActivityLifecycleTest test activities in fullscreen

Launch mOwnerActivity(ActivityA) of the SplitActivityLifecycleTest in
fullscreen to fix failures on devices which use freeform as the default
windowing mode, such as cuttlefish_pc and arc++.
`testTranslucentAdjacentTaskFragment` and
`testActivityLaunchInExpandedTaskFragment` are failing on these devices
because both tests create two activities and expect the first one is
occluded by the second one while setting up the test, but, two
activities are partially overlapped when they are launched in freeform.
Thus, Launch the mOwnerActivity in fullscreen to avoid the issue, other
tests activities' parameters depend on mOwnerActivity so that other
activities will be in the corect size and position.

Bug: 211786060
Test: atest SplitActivityLifecycleTest on devices on devices with
freeform default windowing mode

Change-Id: Idf4e346c7c685e0a4e405a77ec0390e67ce163cd
(cherry picked from commit 21fb96bdc376b8536cad1f591b398f89dc7f9b9a)
diff --git a/tests/framework/base/windowmanager/src/android/server/wm/SplitActivityLifecycleTest.java b/tests/framework/base/windowmanager/src/android/server/wm/SplitActivityLifecycleTest.java
index 7585856..9aed345 100644
--- a/tests/framework/base/windowmanager/src/android/server/wm/SplitActivityLifecycleTest.java
+++ b/tests/framework/base/windowmanager/src/android/server/wm/SplitActivityLifecycleTest.java
@@ -73,7 +73,10 @@
     @Override
     public void setUp() throws Exception {
         super.setUp();
-        mOwnerActivity = startActivity(ActivityA.class);
+        // Launch activities in fullscreen, otherwise, some tests fail on devices which use freeform
+        // as the default windowing mode, because tests' prerequisite are that activity A, B, and C
+        // need to overlay completely, but they can be partially overlay as freeform windows.
+        mOwnerActivity = startActivityInWindowingModeFullScreen(ActivityA.class);
         mOwnerToken = getActivityToken(mOwnerActivity);
     }
 
@@ -561,7 +564,7 @@
     @Test
     public void testTranslucentAdjacentTaskFragment() {
         // Create ActivityB on top of ActivityA
-        Activity activityB = startActivity(ActivityB.class);
+        Activity activityB = startActivityInWindowingModeFullScreen(ActivityB.class);
         waitAndAssertResumedActivity(mActivityB, "Activity B must be resumed.");
         waitAndAssertActivityState(mActivityA, STATE_STOPPED,
                 "Activity A is occluded by Activity B, so it must be stopped.");