currentCompatProperty should point to the compat property that's
currently being evaluated. As soon as we start evaluating a new compat
property, it's invalid by definition. Temporarily disable it then.
Pick-to: 6.6 6.5 6.2
Fixes: QTBUG-109465
Change-Id: I7baba9350ebf488370a63a71f0f8dbd7516bf578
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>