Flaky tests on the CI

[ppkarwasz]

Description

A couple of tests regularly fail on the CI, so often that more than 50% of the runs fail. These tests don't fail locally.

A non exhaustive list:

• JeroMqAppenderTest: the problem here is to determine when the other side of the connection is ready,
• Context data is lost if AsyncLogger and AsyncLoggerConfig are both used #1786, which causes thread context tests to randomly fail in a "doubly async" environment,
• WatchHttpTest: a classic,
• SocketAppenderReconnectTest

[ppkarwasz]

The JeroMqAppenderTest was improved in:

• PR Fix JeroMqAppenderTest race conditions #1754,
• commit 3ecf90e,
• commit 4e8e2eb after a suggestion from JeroMq maintainers,
• commit 497a60d to debug random failures on Windows,
• commit 3b990f4 starts the logger upon event HANDSHAKE_PROTOCOL instead of ACCEPTED.

[ppkarwasz]

The WatchHttpTest was modernized and improved in 4cdcfda and hasn't failed since.

[ppkarwasz]

The SocketAppenderReconnectTest was improved in 39ea3b7 and haven't failed since.