Let AppHibernationManager be mockable

Remove final keyword to let AppHibernationManager be mockable. This can
help testing other classes where the APIs are used.

Test: built successfully
Bug: 183142489
Change-Id: I96eec719d71f549f6a2209fd0db22412c1fa487f
diff --git a/core/api/system-current.txt b/core/api/system-current.txt
index 7bbabb6..4a62b35 100644
--- a/core/api/system-current.txt
+++ b/core/api/system-current.txt
@@ -1832,7 +1832,7 @@
 
 package android.apphibernation {
 
-  public final class AppHibernationManager {
+  public class AppHibernationManager {
     method @NonNull @RequiresPermission(android.Manifest.permission.MANAGE_APP_HIBERNATION) public java.util.List<java.lang.String> getHibernatingPackagesForUser();
     method @RequiresPermission(android.Manifest.permission.MANAGE_APP_HIBERNATION) public boolean isHibernatingForUser(@NonNull String);
     method @RequiresPermission(android.Manifest.permission.MANAGE_APP_HIBERNATION) public boolean isHibernatingGlobally(@NonNull String);
diff --git a/core/java/android/apphibernation/AppHibernationManager.java b/core/java/android/apphibernation/AppHibernationManager.java
index de77848..a36da88 100644
--- a/core/java/android/apphibernation/AppHibernationManager.java
+++ b/core/java/android/apphibernation/AppHibernationManager.java
@@ -33,7 +33,7 @@
  */
 @SystemApi
 @SystemService(Context.APP_HIBERNATION_SERVICE)
-public final class AppHibernationManager {
+public class AppHibernationManager {
     private static final String TAG = "AppHibernationManager";
     private final Context mContext;
     private final IAppHibernationService mIAppHibernationService;