Regularize matrices to fix FGMRES orthogonalization error

[bigfooted]

Proposed Changes

This fixes FGMRES orthogonalization failed errors in the flat plate and the naca0012 testcase (for me).
These can sometimes occur under certain conditions, as a once in a simulation event. When you regularize, the solver simply continues as if nothing ever happened. If there is more going on, this fix will not save your simulation.

• I am submitting my contribution to the develop branch.
• My contribution generates no new compiler warnings (try with --warnlevel=3 when using meson).
• My contribution is commented and consistent with SU2 style (https://su2code.github.io/docs_v7/Style-Guide/).
• I used the pre-commit hook to prevent dirty commits and used pre-commit run --all to format old commits.
• I have added a test case that demonstrates my contribution, if necessary.
• I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.

[bigfooted]

Thanks, Pedro, I've introduced a helper function.