These changes enable the support to handle test data and install or
package them as resources when appropriate.
This change does not handle the GENERATED_TESTDATA or
TEST_HELPER_INSTALLS since there are very few occurrences of these and
we can handle those as special cases.
Finally, in add_qt_test, only append CMAKE_CURRENT_SOURCE_DIR if
the path is not absolute.
Change-Id: Ic20b9749d10e2a09916f2797606116471c64850b
Reviewed-by: Qt CMake Build Bot
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
ec1546afc4