[Tarantool-patches] [PATCH v1] test: fix flaky box/net.box_readahead_gh-3958 test

[Alexander Turenko]

Filed https://github.com/tarantool/test-run/issues/214 , where I
proposed to add a mechanism to elide all past logs for grep_log() and
wait_log().

Let's consider vinyl/compact.test.lua way for a while:

 | -- <prepare>
 | require('log').info(string.rep(" ", 1024))
 | -- <commands that either produce some logs or don't>
 | test_run:wait_log(<...>, <...>, 400) == nil

(Don't miss [1]. Don't sure whether it is still actual after [2].
Please, either check it strongly or keep being on the safe side with
1000/400 magic numbers.)

This way is less intruisive than modifying another test.

CCed Sergey as author of the test case.

[1]: https://github.com/tarantool/tarantool/commit/43965c89fe560fdaa7d916a447a74b9bb3453171
[2]: https://github.com/tarantool/tarantool/commit/437e82ed6bbed98e1fa54cbf8bec178fab50a80d