Fix bugs detected by the address sanitizer

[maxaehle]

Steps to reproduce the underlying issue

Compile SU2 with Clang and -fsanitize=address (and possibly -fno-omit-frame-pointer), and run the testcases as usual. AddressSanitizer warnings appear in the output (if any).

So far, only the tests in serial_regression.py have been analyzed.

Proposed Changes

Depending on the context of the memory leak,

• add delete / delete[] statement
• turn new-allocated arrays into std::vectors, or
• for one bug caused by a delete to a base class pointer, make its destructor virtual.

Related Work

#2211 and #2213 have been detected in the same way, but I'm not sure how to properly fix them.

PR Checklist

Put an X by all that apply. You can fill this out after submitting the PR. If you have any questions, don't hesitate to ask! We want to help. These are a guide for you to know what the reviewers will be looking for in your contribution.

• 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.
• [not necessary] I have added a test case that demonstrates my contribution, if necessary.
• [not necessary] I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.

[pcarruscag]

Nice catches

[jblueh]

The contributions I made are from investigating serial_regression_AD.py in the same manner. parallel_regression.py and parallel_regression_AD.py are checked to a certain extent, too.