8341989: [21u] Back out JDK-8327501 and JDK-8328366

Reviewed-by: goetz

Author: RealCLanger

src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java

@@ -981,7 +981,9 @@ public final ForkJoinWorkerThread newThread(ForkJoinPool pool) {
             boolean isCommon = (pool.workerNamePrefix == null);
             @SuppressWarnings("removal")
             SecurityManager sm = System.getSecurityManager();
-            if (sm != null && isCommon)
+            if (sm == null)
+                return new ForkJoinWorkerThread(null, pool, true, false);
+            else if (isCommon)
                 return newCommonWithACC(pool);
             else
                 return newRegularWithACC(pool);

test/jdk/java/util/concurrent/tck/ForkJoinPool9Test.java

@@ -79,9 +79,6 @@ public void testCommonPoolThreadContextClassLoader() throws Throwable {
             assertSame(ForkJoinPool.commonPool(), ForkJoinTask.getPool());
             Thread currentThread = Thread.currentThread();
 
-            ClassLoader preexistingContextClassLoader =
-                    currentThread.getContextClassLoader();
-
             Stream.of(systemClassLoader, null).forEach(cl -> {
                 if (randomBoolean())
                     // should always be permitted, without effect
@@ -98,11 +95,6 @@ public void testCommonPoolThreadContextClassLoader() throws Throwable {
                     () -> System.getProperty("foo"),
                     () -> currentThread.setContextClassLoader(
                         classLoaderDistinctFromSystemClassLoader));
-            else {
-                currentThread.setContextClassLoader(classLoaderDistinctFromSystemClassLoader);
-                assertSame(currentThread.getContextClassLoader(), classLoaderDistinctFromSystemClassLoader);
-                currentThread.setContextClassLoader(preexistingContextClassLoader);
-            }
             // TODO ?
 //          if (haveSecurityManager
 //              && Thread.currentThread().getClass().getSimpleName()