(ITS#9045) Crashes in cn=config (test050)

[ondra@openldap.org]

Full_Name: Ondrej Kuznik
Version: master
OS: 
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (82.10.24.68)


Every so often (roughly once in a thousand runs or so it seems), a server will
crash in test050 on master. This test replicates cn=config which is not
officially supported yet.

Some output from a gdb session from the core is uploaded here:
ftp://ftp.openldap.org/incoming/test050-crash-master-20190628.txt

It's not clear to me how attrs_dup has reached the attribute at 0x170b6a8 unless
there was another thread messing with the same structure. str2entry2 is running
in another thread, but I wouldn't think it runs on the same entry? Stuff is
optimised out in this one.