8307305: Update debugger tests to support JTREG_TEST_THREAD_FACTORY mode

Reviewed-by: cjplummer

test/hotspot/jtreg/vmTestbase/nsk/share/MainWrapper.java

@@ -46,7 +46,8 @@ public final class MainWrapper {
         Finalizer finalizer = new Finalizer(new FinalizableObject());
         finalizer.activate();
 
-
+        // Some tests use this property to understand if virtual threads are used
+        System.setProperty("main.wrapper", wrapperName);
 
         Runnable task = () -> {
             try {

test/jdk/com/sun/jdi/TestScaffold.java

@@ -513,6 +513,7 @@ abstract public class TestScaffold extends TargetAdapter {
         // Need to change args to run wrapper using command like 'TestScaffold Virtual <app-name>'
         String mainWrapper = System.getProperty("main.wrapper");
         if (mainWrapper != null && !argInfo.targetAppCommandLine.isEmpty()) {
+            argInfo.targetVMArgs += "-Dmain.wrapper=" + mainWrapper;
             argInfo.targetAppCommandLine = TestScaffold.class.getName() + ' '
                     + mainWrapper + ' ' + argInfo.targetAppCommandLine;
         } else if ("true".equals(System.getProperty("test.enable.preview"))) {