Fixed bincount on XLA

[SkafteNicki]

What does this PR do?

Fixes #1466
bincount in torch is not implemented for XLA. We have a fallback solution already for MPS so this PR simply also make XLA computations fallback to that solution.

Not sure about testing, the user in the linked issue is reporting that it is working.

Before submitting

• Was this discussed/approved via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure to update the docs?
• Did you write any new necessary tests?

PR review

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[Borda]

changelog? :)

[codecov]

Codecov Report

Merging #1471 (0d89765) into master (4f1b62b) will increase coverage by 0%.
The diff coverage is 100%.

Additional details and impacted files

@@          Coverage Diff           @@
##           master   #1471   +/-   ##
======================================
  Coverage      90%     90%           
======================================
  Files         213     213           
  Lines       10920   10921    +1     
======================================
+ Hits         9792    9793    +1     
  Misses       1128    1128