GitLab

* Sync parmetis_wrapper with changes in metadata.json

1. In the preprocess.py, make sure that num_partitions is defined as input argument. Also, align 'input_dir' with the input dataset. schema_file is assumed to be located inside the input_dir. Also, graph_stats.txt file is assumed to be present in the input_dir.

2. Use DGL_HOME environment variable so that parmetis_wrapper command can be run anywhere.

* Fix CI test failure cases.

* Addressing CI review comments.

* Addressing CI test failures.

* Applying lintrunner patch