use irange for loops 6 (#66742)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/66742
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: D31705366
fbshipit-source-id: be58222426c192406a7f93c21582c3f6f2082401
