Add Wait() for reshape_op

paddle/fluid/operators/reshape_op.h

@@ -147,6 +147,7 @@ class ReshapeKernel : public framework::OpKernel<T> {
     if (!inplace) {
       out->mutable_data<T>(ctx.GetPlace());
       framework::TensorCopy(*in, ctx.GetPlace(), ctx.device_context(), out);
+      ctx.device_context().Wait();
       // TensorCopy will resize to in_dims.
       out->Resize(out_dims);
     } else {
@@ -169,6 +170,7 @@ class ReshapeGradKernel : public framework::OpKernel<T> {
     auto in_dims = d_x->dims();
     if (!inplace) {
       framework::TensorCopy(*d_out, ctx.GetPlace(), ctx.device_context(), d_x);
+      ctx.device_context().Wait();
       d_x->Resize(in_dims);
     } else {
       d_x->ShareDataWith(*d_out);