[GR-55104] Print the main thread stacktrace in case of exception for TruffleSafepointTest

Author: eregon

truffle/src/com.oracle.truffle.api.test/src/com/oracle/truffle/api/test/TruffleSafepointTest.java

@@ -1850,7 +1850,7 @@ static class TestRootNode extends RootNode {
         @SuppressWarnings("unchecked")
         @Override
         public Object execute(VirtualFrame frame) {
-            waitForLatch(latch);
+            barrier(latch);
             do {
                 Boolean result = callable.call(setup, this);
                 if (result) {
@@ -1957,6 +1957,9 @@ private TestSetup setupSafepointLoop(int threads, NodeCallable callable, Consume
             return setup;
         } catch (Throwable t) {
             if (setup != null && setup.futures != null) {
+                // Print it now, because if some futures also fail they would override the current
+                // exception
+                t.printStackTrace();
                 setup.close();
             } else {
                 c.close();
@@ -2039,8 +2042,9 @@ protected Context createTestContext() {
     private ByteArrayOutputStream outputStream;
 
     @TruffleBoundary
-    private static void waitForLatch(CountDownLatch latch) throws AssertionError {
+    private static void barrier(CountDownLatch latch) throws AssertionError {
         latch.countDown();
+
         boolean interrupted = false;
         while (true) {
             try {