Feature: No-STL and No-LibC tests

### Describe what you are looking for

Our current No-STL and No-LibC aren't always strictly conforming to the expectations and having at least minimal test covergate will help avoid the occasional use of `std::enable_if` and `std::ptrdiff_t`.

### Can you contribute to the implementation?

- [x] I can contribute

### Is your feature request specific to a certain interface?

C++ bindings

### Contact Details

_No response_

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

Inspect the C++ bindings and the existing No-STL and No-LibC configurations first. Add minimal coverage that checks these configurations do not rely on std::enable_if or std::ptrdiff_t, then run the project's existing tests to verify the configurations remain strictly conforming.

Written by the indexing model from the issue text.