Gnn spt (#33)
* rename python1k to small for default dataset.
* add C++ split files
* add an almost empty raw directory in to Java250
* add gitignore files for other directories
* update the README.md for GNN SPT experiments.
* fixed some typo
* add the missing python and java splits
* merged updates from main
* remove unneccessary files
* remove unneccessary files
* remove unneccessary files
Co-authored-by: Wei Zhang <weiz@us.ibm.com>
