Fix ELF output tests for multi-program write-bpf-elf API

The tests were using the old single-program kwargs (:prog-section-name,
:prog-bytes, :relocations) but write-bpf-elf was updated to take
:prog-sections (a list of per-program tuples) for multi-program ELF
support. Update both tests to use the new API.

14/14 tests now pass.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>