qttools: remove ptest installation
qttools: remove ptest installation

Remove last bit of ptest functionality from qttools as no
tests are build anymore.

Signed-off-by: Samuli Piippo <bc256dddab7848ac60359ced88151c0ee7641767@qt.io>

meta-qt5/meta-qt5,schnitzeltony/meta-qt5,schnitzeltony/meta-qt5,meta-qt5/meta-qt5