Only emit global_offset when its non zero. This is to work around the fact that GPUVerify does not support this right now.
Only emit global_offset when its non zero. This is to work around the
fact that GPUVerify does not support this right now.

giuliojiang/gvki,giuliojiang/gvki,mc-imperial/gvki,mc-imperial/gvki,mc-imperial/gvki,giuliojiang/gvki