[Regression] QFile ( QIODevice::Append) append is broken

#include <QFile>
#include <QDebug>

int main(int argc, char *argv[])
{
    QFile file("myNewTestfile.txt");
    bool ret = file.open(QIODevice::WriteOnly);
    Q_ASSERT(ret);
    file.write("Testing First line\nTesting other line");
    ret = file.flush();
    Q_ASSERT(ret);
    file.close();
    Q_ASSERT(!file.isOpen());

    ret = file.open(QIODevice::WriteOnly | QIODevice::Append);
    Q_ASSERT(ret);
    file.write("APPEND new Line");
    ret = file.flush();
    Q_ASSERT(ret);
    file.close();
}