Flaky Test: HTTPClientInternalTests.testChannelAndDelegateOnDifferentEventLoops

[Lukasa]

Just hit this in CI on #335.

Test Case 'HTTPClientInternalTests.testChannelAndDelegateOnDifferentEventLoops' started at 2021-01-25 11:42:35.229
/code/Tests/AsyncHTTPClientTests/HTTPClientInternalTests.swift:465: error: HTTPClientInternalTests.testChannelAndDelegateOnDifferentEventLoops : XCTAssertEqual failed: ("4") is not equal to ("3") - 
/code/Tests/AsyncHTTPClientTests/HTTPClientInternalTests.swift:492: error: HTTPClientInternalTests.testChannelAndDelegateOnDifferentEventLoops : failed - wrong message

[fabianfett]

The implementation changed very much since January, and I haven't seen it since. So I think we should assume it is fixed.