API council requested tweaks to SystemClock.

Test: none
Bug: 73952114
Change-Id: Idd7aae5161a2326920860a6a9c7137369a4d8b3d

api/current.txt

@@ -33093,8 +33093,6 @@ package android.os {
   }
 
   public final class SystemClock {
-    method public static java.time.Clock currentNetworkTimeClock();
-    method public static long currentNetworkTimeMillis();
     method public static long currentThreadTimeMillis();
     method public static long elapsedRealtime();
     method public static long elapsedRealtimeNanos();

core/java/android/os/SystemClock.java

@@ -269,6 +269,7 @@ public final class SystemClock {
      * time or throw.
      *
      * @throws DateTimeException when no accurate network time can be provided.
+     * @hide
      */
     public static long currentNetworkTimeMillis() {
         final IAlarmManager mgr = IAlarmManager.Stub
@@ -302,6 +303,7 @@ public final class SystemClock {
      * time or throw.
      *
      * @throws DateTimeException when no accurate network time can be provided.
+     * @hide
      */
     public static @NonNull Clock currentNetworkTimeClock() {
         return new SimpleClock(ZoneOffset.UTC) {