QQmlProperty crashes on alias properties

QQmlProperty crashes on alias properties if a component with the same name exists.
e.g.

Item {
    property alias test: test
    width: 400
    height: 400
    Rectangle {
        id: test
    }
}

If a component Test.qml exists this will crash if the alias property is accessed via QQmlProperty.

When using qrc files (which are always case sensitive) the issue does not occur.
This is highly relevant for the Qt Quick Designer, since the designer always
uses the native file system and also promotes using alias properties.

I attached a simple example that triggers the crash on Windows.

This is a regression against Qt 5.10.0.

It was introduced by 1e350a8c98d9c98823dde83a6745d2f26a9c0785.
Since exists = QFile::exists(path); (qmltypeloader line 1843) is case insensitive we get a "false postive" for "type names must begin with an uppercase letter".
The ad hoc fix would be to make the check case sensitive for the filename.

This is also relevant for Qt 5.9 if there will be a Qt 5.9.5 release. Qt 5.9.4 does not seem to be affected.