Check check/apply_constraints functions

[mknaranja]

Certain combinations of SI / IP may lead to small negative values in the compartment values. E.g. yesterdays CI reported

[ RUN      ] ParameterStudies.check_ensemble_run_result
Warning: 18 03:04:29.163] [warning] Using RNG with seeds: 3010078739, 3860476826, 216908422, 1362807820, 2764400046, 3563649689.
Warning: 18 03:04:29.164] [warning] Constraint check: Parameter SerialInterval changed from 3.8650 to 3.8496
D:\a\memilio\memilio\cpp\tests\test_parameter_studies.cpp(380): error: Expected: (results[0][i][j]) >= (0.0), actual: -0.0241599 vs 0
 day 48.700000000000017 group 2
[  FAILED  ] ParameterStudies.check_ensemble_run_result (50 ms)

This problem should be studied. The given seeds are a good starting point.