verified-garbage: benchmark scripts and a performance log against AWS-LC

.github/bin/vg_bench.py times 139 operations of the public API on whichever
backend cryptography was built with; vg_bench_compare.py turns passes of
two builds into a Markdown table. VERIFIED_GARBAGE.md gains a Performance
section recording how to reproduce the comparison and the first dated
results against AWS-LC v5.11.0, so later runs can track progress.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Nb78iYb3eVhNTd3P8ypV2X