fix: more stable engine exit

src/main/java/me/topchetoeu/jscript/runtime/Engine.java

@@ -40,7 +40,7 @@ public final class Engine implements EventLoop {
 				try {
 					((Task<Object>)task).notifier.complete(task.runnable.get());
 				}
-				catch (CancellationException e) { throw e; }
+				catch (CancellationException e) { task.notifier.cancel(false); throw e; }
 				catch (RuntimeException e) { task.notifier.completeExceptionally(e); }
 			}
 			catch (InterruptedException | CancellationException e) {

src/main/java/me/topchetoeu/jscript/runtime/Frame.java

@@ -213,7 +213,9 @@ public final class Frame {
 			catch (StackOverflowError e) { throw STACK_OVERFLOW; }
 			catch (EngineException e) { error = e; }
 			catch (RuntimeException e) {
+				if (!(e instanceof CancellationException)) {
 					System.out.println(dbg.getMapOrEmpty(function).toLocation(codePtr, true));
+				}
 				throw e;
 			}
 		}