Fix ONNX While test for CUDA
Fix ONNX While test for CUDA

Summary: We should not be trying to instantiate this op on GPU at this point

Reviewed By: pietern

Differential Revision: D6915576

fbshipit-source-id: 6bdbc93ad12fc67e3001fce1b506fe2895d7b0ba

Yangqing/caffe2,Yangqing/caffe2,Yangqing/caffe2,xzturn/caffe2,Yangqing/caffe2,xzturn/caffe2,xzturn/caffe2,xzturn/caffe2,Yangqing/caffe2,caffe2/caffe2,xzturn/caffe2