use irange for loops (#69533)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/69533
Modified loops in files under fbsource/fbcode/caffe2/ from the format
```
for(TYPE var=x0;var<x_max;x++)
```
to the format
```
for(const auto var: irange(xmax))
```
This was achieved by running r-barnes's loop upgrader script (D28874212) with some modification to exclude all files under /torch/jit and a number of reversions or unused variable suppression warnings added by hand.
Test Plan: Sandcastle
Reviewed By: malfet
Differential Revision: D32837942
fbshipit-source-id: 8663037a38ade8f81bd5e983a614d197ea11f0d1
