988 info on sucessful adaptive step sizing is also shown for fixed step size integrators

[reneSchm]

Changes and Information

Please briefly list the changes (main added features, changed items, or corrected bugs) made:

• Check whether an IntegratorCore is adaptive in OdeIntegrator::advance.
• Add tests for and fix floating point comparisons.

If need be, add additional information and what the reviewer should look out for in particular:

• Checks only whether dt changes during m_core->step calls. After only one change, register m_core as adaptive.
• The result "m_is_adaptive" is stored in OdeIntegrator, and it is only reset (to false) whenever m_core is set.
  • This may prevent under-reporting, e.g. when advance is called repeatedly with dt == dt_max while the ODE admits a larger step size.
  • While currently not possible, this may cause over-reporting if an adaptive m_core were to be configured to be non-adaptive in between advance calls. I think this is acceptable.
• I changed the while loop to a for loop to have the loop statement in one place. This only changes the scope of i. I you prefer the while loop for any reason, I will undo this change.
• I spotted that floating_point_less_equal returned !floating_point_less and corrected it to !floating_point_greater.
  • This turned out to be a bit more complicated than expected, see fixes/tests in changes.
  • The number of new tests could be reduced by using a parametrised test. However, I suspect it would have marginally worse readability.

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• [x] Tests are added for new functionality and a local test run was successful (with and without OpenMP)
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• [x] Corresponding issue(s) is/are linked and addressed
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Closes #988

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 86.66667% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 96.34%. Comparing base (f5e415a) to head (14cb794).

Files	Patch %	Lines
cpp/memilio/math/integrator.cpp	77.77%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #996 +/- ## ======================================= Coverage 96.34% 96.34% ======================================= Files 129 129 Lines 10058 10065 +7 ======================================= + Hits 9690 9697 +7 Misses 368 368 ```

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[mknaranja]

@reneSchm Thanks for the nice fix and the additional work on float comparison operators. Good job.