This will make sure that system files that rust binaries depend on in Windows get packaged into stage0 snapshots as well as into Windows installer.
Currently these include `libgcc_s_dw2-1.dll`, `libstdc++-6.dll` and `libpthread-2.dll`. Note that the latter will need to be changed to `pthreadGC2.dll` once Windows build bots get upgraded to mingw 4.0
Closes#9252Closes#5878Closes#9218Closes#5712