LLVM-12 fix for tensor_new.cpp (#65785)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/65785
Fixes offset to nullptr at fbcode/caffe2/torch/csrc/utils/tensor_new.cpp:206
Test Plan: Sandcastle
Reviewed By: ngimel
Differential Revision: D31250995
fbshipit-source-id: 56c7761787e732180a2537a8aa4346a39e7399a8
