GitLab

* new functional for creating data splits in graph

* minor fix in data split implementation

* apply suggestions from code review
Co-authored-by: Mufei Li <mufeili1996@gmail.com>

* refactoring + unit tests

* fix test file name

* move imports to the top

* Revert "fix test file name"

This reverts commit 126323e38c8de6fdc73c826dccc9048aed8f9634.

* remove nccl submodule

* address linter issues

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Co-authored-by: Mufei Li <mufeili1996@gmail.com>
Co-authored-by: Hongzhi (Steve), Chen <chenhongzhi.nkcs@gmail.com>