[avalanche] Fix a couple issue from D14833
Summary: The log from D14833 fails on some platforms due to path to string conversion, and the chronik test fails due to the persistent avapeers messing with the quorum.
Test Plan:
With chronik:
ninja all check-all
Cross build for windows
Reviewers: #bitcoin_abc, PiRK
Reviewed By: #bitcoin_abc, PiRK
Differential Revision: https://reviews.bitcoinabc.org/D14837