use irange for loops 1 (#66741)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/66741
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: ngimel
Differential Revision: D31705360
fbshipit-source-id: 7115f76e381ad2d98584eb534961c3cbb957ebaa
