Made ActivityManager.forceStopPackage a @SystemApi

This change exposes ActivityManager.forceStopPackage as a @SystemApi so the
Play Store can use it.

Test: Patched in the GTS tests in ag/1753727 and made sure they passed.
Bug: 33021637
Change-Id: I4891f96cde035228ce42aefb726c5fc3c1dd30b3
diff --git a/api/system-current.txt b/api/system-current.txt
index aeb17fb..d179380 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -3858,6 +3858,7 @@
     method public boolean clearApplicationUserData();
     method public void clearWatchHeapLimit();
     method public void dumpPackageState(java.io.FileDescriptor, java.lang.String);
+    method public void forceStopPackage(java.lang.String);
     method public android.util.Size getAppTaskThumbnailSize();
     method public java.util.List<android.app.ActivityManager.AppTask> getAppTasks();
     method public static int getCurrentUser();
diff --git a/core/java/android/app/ActivityManager.java b/core/java/android/app/ActivityManager.java
index 761da35..ff576fe 100644
--- a/core/java/android/app/ActivityManager.java
+++ b/core/java/android/app/ActivityManager.java
@@ -3336,6 +3336,8 @@
      * @see #forceStopPackageAsUser(String, int)
      * @hide
      */
+    @SystemApi
+    @RequiresPermission(Manifest.permission.FORCE_STOP_PACKAGES)
     public void forceStopPackage(String packageName) {
         forceStopPackageAsUser(packageName, UserHandle.myUserId());
     }