Remove shortened timeouts in p2p_invalid_messages

Summary:
The test exhibits occasional failures on the OSX CI machine which has slow networking.
Lowering the timeout brings little to no value, the functions will return as soon as the even happens anyway, and it's better to wait a few more seconds to make sure the issue is real rather than having flaky tests.

Test Plan:

./test/functional/test_runner.py p2p_invalid_messages

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D14340