Workaround fix for JVM Crash Issue while refreshing 'ProblemTreeViewer'

This workaround ensures that the action is performed on the display thread properly. However, the bug still exists in the SWT/JFace which needs to be fixed. Other plugins using `getTreeViewer().refresh()` from `PackageExplorerPart` are prone to crash the JVM as well.

Fixes bndtools#4854
Signed-off-by: Amit Kumar Mondal <admin@amitinside.com>

bndtools.core/src/bndtools/explorer/Model.java

@@ -103,12 +103,8 @@ void onUpdate(Runnable runnable) {
 
 	void update() {
 		dirty.set(true);
-		if (Display.getCurrent() == null) {
-			Display.getDefault()
-				.asyncExec(this::update0);
-		} else {
-			update0();
-		}
+		Display.getDefault()
+			.asyncExec(this::update0);
 	}
 
 	private void update0() {