Increase timeout in avalanche test

Summary:
When running with TSAN the query can be delayed so much that the timeout
is not enough.
Bumping the timeout by an order of magnitude should prevent the CI
failure without slowing the test in the average case.

Test Plan: Run the CI build-tsan build configuration.

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D5152