collect_results.py can not handle multiple FPGA targets in folder

[benlcb]

When running the collect_results script on folders containing results for multiple targets (e.g. xcvu440 and xc7a200), the result tables xcvu440.csv and xc7a200.csv will not contain all results.

I didn't look further into this but it seems that only contraint/clock delay will be included that are available for both targets (e.g. if on one target the minimal clock delay is 15000, any lower clock delays for the other target will be omitted).

Writing this down here so anyone using this in the future is aware.