quantization: unexpected casting of tensor min and max to int in histogram observer

[vkuzo]

🐛 Describe the bug

Originally reported in https://discuss.pytorch.org/t/casting-to-int-of-data-min-and-max-in-histogramobserver/159316

There is code in HistogramObserver which casts the tensor min and max to integers before calculating the histogram: https://github.com/pytorch/pytorch/blame/a9ba3fe1dbf2cea45c9a7e723010c27c211f7fe3/torch/ao/quantization/observer.py#L1143. It's unclear on why this is here since we want the histogram bins be as accurate as possible, we should verify if there is a reason for having this and remove it if there isn't a reason.

Versions

master

cc @jerryzh168 @jianyuh @raghuramank100 @jamesr66a @jgong5 @Xia-Weiwen @leslie-fang-intel @vkuzo

[vkuzo]

looks like this was added by #45630 by mistake, so this is a bug

[vkuzo]

#83755 will address this

[andrewor14]

@vkuzo Is this fixed? Should we close it?