This will allow for the Qt Creator's CMake build only qtcreator
target to be selected as runnable.
Similar to qmake's qtc_runnable or Qbs's qtcRunnable features.
Fixes: QTCREATORBUG-25908
Change-Id: I6416873d0ad9cfec4960d98fc4b289ec98cc58b1
Reviewed-by: Eike Ziller <eike.ziller@qt.io>