GitLab

* Fix coo_sort

* Add COOSort test

* Fix

* omp

* coo2csr can benefit from sorted coo

* Add more test code

* Add LIBCXX_ENABLE_PARALLEL_ALGORITHMS to Makefile

* upd

* Turn off LIBCXX_ENABLE_PARALLEL_ALGORITHMS by default
Co-authored-by: Ubuntu <ubuntu@ip-172-31-51-214.ec2.internal>