[REG: 5.11.1->5.11.2] QNAM normalizes urls

Since a0ebd98f58b2d92c34fafbc620f024caa36bf0ad ( https://codereview.qt-project.org/#/c/236585/ ) all paths are normalized. This causes issues in cases where the server differentiates / and // in a path. (I think /./ and /../ are also valid in paths, but it is fine to normalize them). Having an empty name in a path is a way to give empty parameter for path patterns.

For example, with:

QNetworkRequest(QUrl("http://example.com/some//path"))

The server now gets:

/some/path

wget, curl, chrome and firefox for example passes // in paths to the server as is, but normalizes /./ and /../ cases.