remove data sync in tensor's ToString

mindspore/core/ir/tensor.cc

@@ -542,7 +542,6 @@ std::string Tensor::ToStringInternal(int limit_size) const {
   std::ostringstream buf;
   auto dtype = Dtype();
   MS_EXCEPTION_IF_NULL(dtype);
-  data_sync(false);
   buf << "Tensor(shape=" << ShapeToString(shape_) << ", dtype=" << dtype->ToString() << ", value=";
   if (limit_size <= 0 || DataSize() < limit_size) {
     // Only print data for small tensor.
@@ -568,7 +567,6 @@ std::string Tensor::ToStringRepr() const {
   std::ostringstream buf;
   auto dtype = Dtype();
   MS_EXCEPTION_IF_NULL(dtype);
-  data_sync(false);
   buf << "Tensor(shape=" << ShapeToString(shape_) << ", dtype=" << dtype->ToString()
       << ", value=" << ((data().ndim() > 1) ? '\n' : ' ') << data().ToString(data_type_, shape_, true) << ')';
   return buf.str();