Add a CMake flag to set array index checking

[ktbolt]

I've added CMake commands to set the ENABLE_ARRAY_INDEX_CHECKING C++ directive used by the Array templates to check Array indices (https://github.com/SimVascular/svFSIplus/issues/146).

The CMake ENABLE_ARRAY_INDEX_CHECKING variable should be enabled when testing.

[mrp089]

For future reference, this PR (with array checking enabled) almost doubles the execution times for our tests (before/after):

• Ubuntu 20: 14 / 28 min
• Ubuntu 22: 13 / 39 min
• macOS 12: 25 / 27 min

I think it's fine to merge, but @ktbolt, @MatteoSalvador, please let me know if not.

We can keep this in mind if we want to split up testing in the future (e.g., every commit, every PR, nightly, weekly).