Add ahead tests

[ikalash]

This PR adds a number of new tests for the AHEAD problems. A few things to be aware of:

• All tests pass on Irina's RHEL9 machine, hayka. I am not sure what will happen in the nightly test harness. It is possible that some of the test tolerance need to be loosened a bit for all tests to pass there. We can see what happens when they run.
• All the new Schwarz test compare the number of Schwarz iterations needed for convergence with a reference array of these values. This means that if a change is introduced that doesn't change the solution but changes the # Schwarz iterations, a test will fail and needs to be rebaselined. I would like to keep this behavior b/c I want us to be aware if we make a change that changes the # Schwarz iterations, whether for the good or bad.
• It takes about 32 mins on Irina's machine to run all tests. Many users will not be patient enough for this. Some tests can be moved to the longer test category. I will let @lxmota do this after this is merged in based on any criteria he has for how fast the core tests should run.
• There are still some tests that need to be added for full coverage; see the comments of Add tests for AHEAD problems #99 . I will work on this when I'm back from foreign travel.

[lxmota]

There seem to be conflicts because both the ubuntu and macos tests fail. I'll try to checkout this branch separately and resolve the conflicts.

[ikalash]

Thanks @lxmota . It could be a tolerance issue - I did specify very tight tolerances. I am not going to have time to look at this now b/c I am flying out tomorrow morning. It would be great if these could get fixed/merged in so that when you/others check things in, the ahead tests will be run.

[lxmota]

Yes, I see that some tolerances are too tight. I’ll take a look.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.45%. Comparing base (b02a962) to head (6c079f0).
Report is 40 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #113      +/-   ##
==========================================
+ Coverage   93.42%   93.45%   +0.02%     
==========================================
  Files          16       16              
  Lines        3956     3956              
==========================================
+ Hits         3696     3697       +1     
+ Misses        260      259       -1     

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[ikalash]

CI tests are clean so I will merge in.