Bringing B2-Style Test Granularity to CMake

https://cppalliance.org/alan/2025/07/10/Alan.html

B2‑style granularity is added to Boost’s CMake integration by building the test executable, post‑build extracting test names via a listing flag, generating a .cmake file with individual add_test entries, and including it with TEST_INCLUDE_FILES, enabling separate reporting and selective runs.