FrameCapture: Add compare_trace_screenshots.py fuzz_ab command Also add `compare_with_fuzz_factors()` and `get_common_files()` helper functions to avoid code duplication. Bug: b/294882956 Change-Id: Ibc12df0ec033db502930e8a7ea3b7be8b17a79b3 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6932073 Reviewed-by: Cody Northrop <cnorthrop@google.com> Commit-Queue: Cody Northrop <cnorthrop@google.com>