I don't expect a benchmarking app to be throttled by the OS under any circumstances--ideally the benchmarking app would run on the raw hardware, with no second-guessing by the OS about whether it should be throttled because the battery is down to 10%, or because some other process would like some network or CPU, etc.

The way this probably should work is that the benchmarking apps themselves have a flag telling the OS they want all cores at full power all of the time, instead of having to hardcode this list into the OS. (Perhaps this could be one of the permissions you have to accept when installing the app.)