Temporarly disable the getavaaddr_interval_test

Summary: This test fails regularly on CI but I'm unable to make it fail on any of my machines, after thousands of runs under the slowest possible conditions. Let's disable it for now as it's disturbing the reviews.

Test Plan:

./test/functional/test_runner.py abc_p2p_getavaaddr

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D17656