[jnc_sample] only add sample_03_dialog on windows and native linux build
[jnc_sample] only add sample_03_dialog on windows and native linux build

on Mac test will fail cause using QT in Release build requires setting Framework
dirs (during Debug build it will link tho -- due to -rpath);

on Linux cross build amd64 -> x86 test will fail if QT5 multilib is not
installed, and it's troublesome to install it on some distros

for now, disable the test unless it's likely to work out-of-the-box

vovkos/jancy,vovkos/jancy,vovkos/jancy,vovkos/jancy,vovkos/jancy