Map Bioconductor source files to test files, avoiding false positives. Tightens filename and content-based matching; handles short names like "t".
get_source_test_mapping_Bioc_nstf(pkg_source_path, test_dir)data.frame with columns: source_file, test_file, evidence, has_tests
Character; path to the package root (expects R/ under it).
Character; path to tests directory (e.g., file.path(pkg, "tests"))