"wait" seem to be ignored when "must_die" is used

[jdesgats]

I have a test that involves making nginx kill itself in the init_worker phase (a worker kills the master process and then kill itself, just in case), so my test look like that

--- wait: 1
--- error_log
[crit]
--- must_die: 0

but the error_log started to randomly fail at some point, I tracked this down to the fact that the error_log doesn't get the critical log lines, but they do appear in the t/servroot/error.log file, so I guess they are not written yet at that point. Setting a ridiculously high wait doesn't help as it seem to be ignored in that case.