Adapt JDK-8351927: Change VirtualThread implementation to use use FJP delayed task handling

Author: mur47x111

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/thread/Target_java_lang_VirtualThread.java

@@ -100,11 +100,6 @@ public final class Target_java_lang_VirtualThread {
     @TargetElement(onlyWith = JDK21OrEarlier.class) //
     private static ScheduledExecutorService UNPARKER;
 
-    @Alias //
-    @InjectAccessors(DelayedTaskSchedulersAccessor.class) //
-    @TargetElement(onlyWith = JDKLatest.class) //
-    private static ScheduledExecutorService[] DELAYED_TASK_SCHEDULERS;
-
     /** Go through {@link #nondefaultScheduler}. */
     @Alias //
     @InjectAccessors(SchedulerAccessor.class) //
@@ -134,10 +129,6 @@ public final class Target_java_lang_VirtualThread {
     @TargetElement(onlyWith = JDK21OrEarlier.class)
     private static native ScheduledExecutorService createDelayedTaskScheduler();
 
-    @Alias
-    @TargetElement(onlyWith = JDKLatest.class)
-    private static native ScheduledExecutorService[] createDelayedTaskSchedulers();
-
     @SuppressWarnings("unused")
     private static final class AlwaysFalseAccessor {
         static boolean get(Target_java_lang_VirtualThread vt) {
@@ -192,28 +183,6 @@ private static synchronized ScheduledExecutorService initializeDelayedTaskSchedu
         }
     }
 
-    private static final class DelayedTaskSchedulersAccessor {
-        private static volatile ScheduledExecutorService[] delayedTaskSchedulers;
-
-        @SuppressWarnings("unused")
-        public static ScheduledExecutorService[] get() {
-            ScheduledExecutorService[] result = delayedTaskSchedulers;
-            if (result == null) {
-                result = initializeDelayedTaskScheduler();
-            }
-            return result;
-        }
-
-        private static synchronized ScheduledExecutorService[] initializeDelayedTaskScheduler() {
-            ScheduledExecutorService[] result = delayedTaskSchedulers;
-            if (result == null) {
-                result = createDelayedTaskSchedulers();
-                delayedTaskSchedulers = result;
-            }
-            return result;
-        }
-    }
-
     @SuppressWarnings("unused")
     private static final class SchedulerAccessor {
         static Executor get(Target_java_lang_VirtualThread self) {