Avoid function call overhead and parallelize the creation of the edit and sculpt mode lines index buffers. Also, remove an extra index that was added for each curve when there are no cyclic curves. Though ideally these index buffers would be generated on the GPU, this simple change makes this part of the GPU data building almost 5x faster (from 1.23 ms to 0.25 ms for curves with 80 thousand points). Pull Request: https://projects.blender.org/blender/blender/pulls/133897