This PR simply aims to cleanup, fix dates, and remove any "fluff" from the test/regression cases in SU2. This will not affect the cases in the V&V folder.

Its a purely maintenance pr, while I have some time to be productively unproductive.

• 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 have added a test case that demonstrates my contribution, if necessary.
• I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.