Add support for missing return obj from to function on custom batch objects

[tchaton]

What does this PR do?

This PR adds support for moving custom data object on device where the object doesn't return self from the to function.

Example: https://github.com/intel-isl/Open3D-ML/blob/master/ml3d/torch/dataloaders/concat_batcher.py#L484

Does your PR introduce any breaking changes ? If yes, please list them.

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[codecov]

Codecov Report

Merging #8433 (a7aa566) into master (ae1fd6a) will decrease coverage by 0%.
The diff coverage is 100%.

@@          Coverage Diff           @@
##           master   #8433   +/-   ##
======================================
- Coverage      93%     92%   -0%     
======================================
  Files         216     217    +1     
  Lines       14109   14113    +4     
======================================
- Hits        13083   13018   -65     
- Misses       1026    1095   +69     

[carmocca]

Not a fan of us doing this but I guess it doesn't hurt. A tool like mypy would have reported the bug

[ethanwharris]

LGTM 😃