Sync tmp directory

[b-chu]

Description of changes:

Use a temporary directory based on remote and split instead of a randomly created one so the same directory will be used in distributed training

Issue #, if available:

#293

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[karan6181]

Please also try running the basic dataset iteration on more than 1 gpu (maybe 2, 4, or 8) multiple times with local=None to ensure it works as expected.