Update on "[ET] correcting cpu ref quantize_per_channel logic to align with ATen"

# Context

The quantize_per_channel was not perfectly aligned with the ATen implementation, and demonstrated errors when specifying different axis. This bug wasn't distinctly acknowledged given that the test cases only has one test for the whole operator. In order to align more closely with ATen this change simply does a single loop imlpementation with direct channel index calculation over the old `apply_over_dim_list` approach.

# Changes

We change the core logic for quantize_per_channel to more properly align with ATen's implementation, and we also change it from `apply_over_dim_list` approach to a single loop implementation with direct channel index calculation. This also adds more comprehensive testing for quantize_per_channel so that a bug isn't missed again.

Differential Revision: [D77746130](https://our.internmc.facebook.com/intern/diff/D77746130/)

[ghstack-poisoned]

Author: morelos