Remove awt_makecube.cpp

This is from a code review following the jigsaw source file restructuring:

The file ./windows/native/common/awt_makecube.cpp is a bit strange. It is not a shared file; instead it's a stand-alone binary with a main() function. It is not compiled by any makefile targets. If this file is actually used, I suggest moving it to a better location (windows/native/launchers?), and starting to compile it with the build. (Stuff that's not built regularly is doomed to bit rot.) It if is not used, I suggest we remove it.