Make tensor device correct when ACCELERATE_TORCH_DEVICE is defined
Author: kiszk
Pull request: yes

# What does this PR do?

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Fixes #31750

This PR fixes the issue of returning an incorrect device (`cpu`) of tensors passed to a model with `accelerate` when `ACCELERATE_TORCH_DEVICE` is defined as `privateuseone:0`. When known accelerators are not available, a function should check whether `ACCELERATE_TORCH_DEVICE` is defined or not before returning `cpu`.

It looks hard to write a test problem with `privateuseone:0`. I manually tested the issue was fixed with this PR. Any idea to add tests are appreciated.

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## Who can review?

@muellerzr  @SunMarc

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Comments:
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