[Bug 53986] wininet:http - test_concurrent_header_access() sometimes fails on Windows 7 & 8

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=53986

--- Comment #1 from François Gouget  ---
This often comes with a missing header error. For instance on 2022-12-19 on
w7u-adm:

http.c:838: Option HTTP_QUERY_CONTENT_ENCODING -> 0  text/plain;charset=UTF-8
http.c:7825: Test failed: HttpQueryInfoA failed 6
0fac:http: 5101 tests executed (0 marked as todo, 0 as flaky, 1 failure), 0
skipped.
http.c:7826: Test failed: header missing
wininet:http:0fac done (2) in 9s 4725B

This also shows that the test summary does not always account for these two
failures which means there is a synchronization issue of some sort in
test_concurrent_header_access().