[caffe2][a10] Move down pragma pop to properly suppress warning 4522 (#49233)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/49233
As the comments on line 160, say we should suppress this overly aggressive warning with MSVC:
```
caffe2\tensorbody.h_ovrsource#header-mode-symlink-tree-only,headers\aten\core\tensorbody.h(1223): warning C4522: 'at::Tensor': multiple assignment operators specified
```
However, in order to remove the warning, the closing brace of the class must be between the`#pragma warning` push and its corresponding pop. Move the pop down to ensure that.
Test Plan: Built locally using clang for Windows without buck cache, confirmed the warning resolved
Reviewed By: bhosmer
Differential Revision: D25422447
fbshipit-source-id: c1e1c66fb8513af5f9d4e3c1dc48d0070c4a1f84
