Port addon-module cmake tests from Qt5 to Qt6

Many modules that have been ported to Qt6 have omitted porting the tests/auto/cmake test cases, which were based on Qt5 and older cmake.

Preferably these tests should be ported to Qt6. By grepping at least following repositories have such cases to be ported: qtconnectivity, qtremoteobjects, qtserialport, qtwebchannel, qtcharts, qtscxml, qtserialbus, qtwebsockets, qtlocation *)

*) qtlocation is still in-progress though, not possible to address at the time of this writing