Context

Contributes #6091

The bench script only ever run the debugger on one level of inbox. Some bench scenario output several. This MR makes sure there is only one level.

A better fix would be to read an unbounded number of levels, but this will do for now IMO.

I'm guessing there would be another fix, by sending a bit more profile on stdin, and stopping when "no inputs" is read.

The MR also contains some tweak to account for gas fees in scenarios.

Manually testing the MR

Run the benchs

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