title: how to suppress console output from QWebEngineView errors?
body: <p>I get the following error if I create a QWebEngineView instance from Python instances in different working directories:</p>
  <pre><code>[2452:9872:1108/052617.050:ERROR:cache_util_win.cc(21)] Unable to move the cache: Access is denied. (0x5)
  [2452:9872:1108/052617.050:ERROR:cache_util.cc(135)] Unable to move cache folder C:\Users\Adam\AppData\Local\python\QtWebEngine\Default\GPUCache to C:\Users\Adam\AppData\Local\python\QtWebEngine\Default\old_GPUCache_000
  [2452:9872:1108/052617.051:ERROR:disk_cache.cc(184)] Unable to create cache
  [2452:9872:1108/052617.056:ERROR:shader_disk_cache.cc(606)] Shader Cache Creation failed: -2
  </code></pre>
  <pre><code>from PyQt5 import QtCore, QtGui, QtWidgets, QtWebEngineWidgets
  from PyQt5.QtCore import Qt
  app = QtWidgets.QApplication([])
  x = QtWebEngineWidgets.QWebEngineView()
  x.load(QtCore.QUrl('http://example.com/'))
  </code></pre>
  <p><a href="https://i.stack.imgur.com/INrC7.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/INrC7.png" alt="enter image description here" /></a></p>
  <p>It seems this is a known issue and will be fixed in QT6: <a href="https://bugreports.qt.io/browse/QTBUG-66014" rel="nofollow noreferrer">https://bugreports.qt.io/browse/QTBUG-66014</a></p>
  <p>But in the meantime, how can I suppress this message? I tried changing <code>QtCore.qInstallMessageHandler</code> and also <code>x.page().javaScriptConsoleMessage = lambda self, level, msg, line, sourceID: None</code>, neither affected this message.</p>