Don't error out if a FBInfer run doesn't generate a report.
Review Request #12138 — Created March 11, 2022 and submitted
The FBInfer post-processing code made the assumption that reports would
always be provided after a run. This doesn't appear to always be the
case in production.
The tool now checks for the presence of a report and returns empty
results if not found.
Unit tests pass.
Tested with a real FBInfer run that generated no results. Verified
no errors were logged.