Force creation of default WebEngineProfile

Make sure that the default QWebEngineProfile is created first. This
creates the default WebEngineContext, which in turn initializes global
things like AtExitManager.

Task-number: QTBUG-49557
Change-Id: I9e8f6bd24edd7f4c7e8bb38d91a2c09631824828
Reviewed-by: Michael Brüning <michael.bruning@theqtcompany.com>

src/webengine/api/qquickwebengineprofile.cpp

@@ -165,6 +165,8 @@ void QQuickWebEngineProfilePrivate::downloadUpdated(const DownloadItemInfo &info
 QQuickWebEngineProfile::QQuickWebEngineProfile()
     : d_ptr(new QQuickWebEngineProfilePrivate(new BrowserContextAdapter(false)))
 {
+    // Sets up the global WebEngineContext
+    QQuickWebEngineProfile::defaultProfile();
     d_ptr->q_ptr = this;
 }