Don't explicitly launch test activity in fullscreen in AssistantStackTests

This is a partial revert of aosp/1442704.

With aosp/1473879, the tests take the default display windowing
mode into account when asserting the windonwing mode of the test
activity, but we still forcefullly launch them in fullscreen in
some places (introduced by aosp/1442704), so they contradict with
each other.

Bug: 190327854
Test: AssistantStackTests
Change-Id: I9661e6ef54bcb6709cfe1e8ca15c032c804db970
(cherry picked from commit 152360e7bf5c51ba16f4d1e07701a69575255d06)
diff --git a/tests/framework/base/windowmanager/app/src/android/server/wm/app/AssistantActivity.java b/tests/framework/base/windowmanager/app/src/android/server/wm/app/AssistantActivity.java
index 82c3770..2258da2 100644
--- a/tests/framework/base/windowmanager/app/src/android/server/wm/app/AssistantActivity.java
+++ b/tests/framework/base/windowmanager/app/src/android/server/wm/app/AssistantActivity.java
@@ -47,13 +47,14 @@
             final Intent launchIntent = new Intent();
             launchIntent.setComponent(launchActivity)
                     .setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
-            final ActivityOptions activityOptions = ActivityOptions.makeBasic();
-            activityOptions.setLaunchWindowingMode(WINDOWING_MODE_FULLSCREEN);
             if (getIntent().hasExtra(EXTRA_ASSISTANT_DISPLAY_ID)) {
-                activityOptions.setLaunchDisplayId(Integer.parseInt(getIntent()
+                ActivityOptions displayOptions = ActivityOptions.makeBasic();
+                displayOptions.setLaunchDisplayId(Integer.parseInt(getIntent()
                         .getStringExtra(EXTRA_ASSISTANT_DISPLAY_ID)));
+                startActivity(launchIntent, displayOptions.toBundle());
+            } else {
+                startActivity(launchIntent);
             }
-            startActivity(launchIntent, activityOptions.toBundle());
         }
 
         // Enter pip if requested
diff --git a/tests/framework/base/windowmanager/src/android/server/wm/AssistantStackTests.java b/tests/framework/base/windowmanager/src/android/server/wm/AssistantStackTests.java
index 55ae8a0..0ec2bef 100644
--- a/tests/framework/base/windowmanager/src/android/server/wm/AssistantStackTests.java
+++ b/tests/framework/base/windowmanager/src/android/server/wm/AssistantStackTests.java
@@ -200,9 +200,9 @@
             removeRootTasksWithActivityTypes(ACTIVITY_TYPE_ASSISTANT);
         }
 
-        // Launch an assistant activity on top of an existing fullscreen activity, and ensure that
-        // the fullscreen activity is still visible and on top after the assistant activity finishes
-        launchActivityOnDisplay(TEST_ACTIVITY, WINDOWING_MODE_FULLSCREEN, mAssistantDisplayId);
+        // Launch an assistant activity on top of an existing activity, and ensure that the activity
+        // is still visible and on top after the assistant activity finishes
+        launchActivityOnDisplay(TEST_ACTIVITY, mAssistantDisplayId);
         try (final AssistantSession assistantSession = new AssistantSession()) {
             assistantSession.setVoiceInteractionService(ASSISTANT_VOICE_INTERACTION_SERVICE);