[libc++] Refactor of ASan annotation functions (#74023)

This commit refactors the ASan annotation functions in libc++ to reduce
unnecessary code duplication. Additionally it adds a small optimization.

- Eliminates two redundant function versions by utilizing the
`[[maybe_unused]]` attribute and guarding function bodies with `#ifndef
_LIBCPP_HAS_NO_ASAN`.
- Introduces an additional guard to an auxiliary function, allowing the
removal of a no-ops function body. This approach avoids relying on the
optimizer for code elimination.

Fixes #73043