Populate late-stamped library versions

Summary: Populate late-stamped ELF build-info library_versions from linker dependency metadata instead of leaving the field empty.

• For C++ links, thread the final LinkArgs into stamp_build_info() and derive the same semicolon-separated, deduped, truncated version string used by the linker-wrapper build-info path.
• For native Python packaging, reuse the PAR manifest shared-library metadata computation and copy it into the late-stamped _build_info before the runtime binary is stamped.

Reviewed By: ambv

Differential Revision: D106923418

fbshipit-source-id: 1711d8e2b47f3163577a160c0e915cdbb6c342fd