Fix incorrect test

Author: vietj

src/test/java/io/vertx/core/ContextTaskTest.java

@@ -178,17 +178,14 @@ private void testOpFromAnotherEventLoop(BiConsumer<ContextInternal, Handler<Void
     waitFor(2);
     ContextInternal ctx = contextSupplier.get();
     createEventLoopContext().nettyEventLoop().execute(() -> {
-      AtomicBoolean flag = new AtomicBoolean(true);
       op.accept(ctx, v2 -> {
         if (isSchedule) {
           assertNull(Vertx.currentContext());
         } else {
           assertSame(ctx, Vertx.currentContext());
         }
-        assertFalse(flag.get());
         complete();
       });
-      flag.set(false);
       complete();
     });
     await();