Consistency of maxevals property with evals property

[nikohansen]

Should the property DataSet.maxevals rather return DataSet.maxfgevals when testbedsettings.current_testbed.has_constraints, to be consistent with the evals property? This would avoid code like this

if testbedsettings.current_testbed.has_constraints:
    # maxevals is inconsistent in that case
    maxevals_column = entry.maxfgevals
else:
    maxevals_column = entry.maxevals

Could there be undesired side effects?

[nikohansen]

Probably in the current ERT value computation with the constrained testbed, the unsuccessful runs are for this reason by a factor of 2 off.

[nikohansen]

To be continued with #2106.