This PR replace the bls loading logic in node.sh with logic in harmony binary. These tests are to ensure that the BLS loading is still functioning for the following scenario:
- New binary with old node.sh
- bls keys in bls dir (w/o persist passphrase)
- single bls key (with passphrase from file or prompt)
- New binary with new node.sh
- bls keys in bls dir (w/o persist passphrase)