Add method waitForReferenceProcessing() in Reference.java

	- Add private static method waitForReferenceProcessing() in
	java.lang.ref.Reference.java to adapt for openjdk TLS 1.3 
	regression tests. 
	
	
Signed-off-by: Lin Hu <linhu@ca.ibm.com>

jcl/src/java.base/share/classes/java/lang/ref/Reference.java

@@ -88,6 +88,12 @@ static class ClearBeforeEnqueue {
 			  }
 			});
 	}
+
+	/* The method waitForReferenceProcessing() is not used directly, just adapt for openjdk regression tests for TLS 1.3 */
+    private static boolean waitForReferenceProcessing() throws InterruptedException {
+    		return waitForReferenceProcessingImpl();
+    }
+
 	/*[ELSE]
 	static {
 		SharedSecrets.setJavaLangRefAccess(new JavaLangRefAccess() {