I just faced the same problem and threw together a quick post-processing script that removes any redundant "Set Bed Temperature" and "Wait for Bed Temperature" commands: RemoveReheat.py
Just save the py file in your Cura scripts Folder (on Windows %AppData%/cura/<version>/scripts), restart Cura, and enable the "Remove Reheat" by going to Extensions -> Post-Processing -> Modify G-Code -> Add a script.
The script removes the waits only if the target bed temp did not change.