Summary: Batch creation now does not iterate over V**2 vertex pairs, but over V vertices and generates E/V random edges for each one. Assuming there is an index over :V(id), this is much more efficient and supports larger vertex counts (Ferenc: modify the test config as desired). An additional requirement is that E/V (for each worker) is a whole number. Reviewers: mferencevic Reviewed By: mferencevic Subscribers: pullbot Differential Revision: https://phabricator.memgraph.io/D860