Bug 566439 - removed "no tests found..." dialog for JUnit 5

Removed the "No tests found with test runner 'JUnit 5'" dialog. That
error was typically shown after manually terminating the test launch,
where it's just unnecessary noise.
To leave a debugging aid, this message is now logged to the error log.

Change-Id: I893c5e460b9e365eb287b84dfb62220aa24b06ec
Signed-off-by: Julian Honnen <julian.honnen@vector.com>
diff --git a/org.eclipse.jdt.junit/src/org/eclipse/jdt/internal/junit/ui/TestRunnerViewPart.java b/org.eclipse.jdt.junit/src/org/eclipse/jdt/internal/junit/ui/TestRunnerViewPart.java
index 797b1ee..7120eeb 100644
--- a/org.eclipse.jdt.junit/src/org/eclipse/jdt/internal/junit/ui/TestRunnerViewPart.java
+++ b/org.eclipse.jdt.junit/src/org/eclipse/jdt/internal/junit/ui/TestRunnerViewPart.java
@@ -772,7 +772,7 @@
 				warnOfContentChange();
 			});
 			stopUpdateJobs();
-			showMessageIfNoTests();
+			logMessageIfNoTests();
 
 			// When test session ended, apply user sorting criterion
 			getDisplay().asyncExec(new Runnable() {
@@ -1531,15 +1531,13 @@
 			updateRerunFailedFirstAction();
 		});
 		stopUpdateJobs();
-		showMessageIfNoTests();
+		logMessageIfNoTests();
 	}
 
-	private void showMessageIfNoTests() {
+	private void logMessageIfNoTests() {
 		if (fTestRunSession != null && TestKindRegistry.JUNIT5_TEST_KIND_ID.equals(fTestRunSession.getTestRunnerKind().getId()) && fTestRunSession.getTotalCount() == 0) {
-			Display.getDefault().asyncExec(() -> {
-				String msg= Messages.format(JUnitMessages.TestRunnerViewPart_error_notests_kind, fTestRunSession.getTestRunnerKind().getDisplayName());
-				MessageDialog.openInformation(JUnitPlugin.getActiveWorkbenchShell(), JUnitMessages.TestRunnerViewPart__error_cannotrun, msg);
-			});
+			String msg= Messages.format(JUnitMessages.TestRunnerViewPart_error_notests_kind, fTestRunSession.getTestRunnerKind().getDisplayName());
+			Platform.getLog(getClass()).error(msg);
 		}
 	}