QtDeclarative test example gets installed during make install

The example qml test in qtdeclarative/examples/qmltest gets built when Qt is compiled and gets installed to $PREFIX/tests during "make install". For binary packages, this is the only thing that ends up in $PREFIX/tests, as the real tests are excluded from package builds.

Assuming that this example is still useful (i.e. more useful for education than looking at a real test, it should get installed somewhere under $PREFIX/examples/qtdeclarative rather than under tests.