Make documentLaunchMode="never" activity don’t create task

Activity that specify “documentLaunchMode="never" should not launched
into a new document even if the Intent contains
FLAG_ACTIVITY_NEW_DOCUMENT.

This CL overrides the behavior of the FLAG_ACTIVITY_NEW_DOCUMENT and
FLAG_ACTIVITY_MULTIPLE_TASK flags to make the definition consistent
with documentation.

Bug: 113840793
Test: atest IntentTests
Change-Id: I9b96e7fe0306d54b8f833873bcad8e0508dd3aa8

services/core/java/com/android/server/wm/ActivityStarter.java

@@ -2691,7 +2691,8 @@ class ActivityStarter {
                     launchFlags |= Intent.FLAG_ACTIVITY_NEW_DOCUMENT;
                     break;
                 case ActivityInfo.DOCUMENT_LAUNCH_NEVER:
-                    launchFlags &= ~FLAG_ACTIVITY_MULTIPLE_TASK;
+                    launchFlags &=
+                            ~(Intent.FLAG_ACTIVITY_NEW_DOCUMENT | FLAG_ACTIVITY_MULTIPLE_TASK);
                     break;
             }
         }