run test_dbi_conn_transaction_commit() and test_dbi_conn_transaction_rollback() only if the driver supports transactions; implemented test_dbi_conn_rollback_to_savepoint() and test_dbi_conn_release_savepoint()
run test_dbi_conn_transaction_commit() and test_dbi_conn_transaction_rollback() only if the driver supports transactions; implemented test_dbi_conn_rollback_to_savepoint() and test_dbi_conn_release_savepoint()

cention-nazri/libdbi-drivers,cention-nazri/libdbi-drivers,cention-nazri/libdbi-drivers,cention-nazri/libdbi-drivers