Not sure why, but SYSCTL_OUT() can sometimes keep returning ENOMEM in sysctl_jail_list(). Because of this, jls(8) could enter into an endless loop. The strange thing is, that we can call jls(8) while the other one is in loop and it will succeed - SYSCTL_OUT() will not return ENOMEM there.
Not sure why, but SYSCTL_OUT() can sometimes keep returning ENOMEM
in sysctl_jail_list(). Because of this, jls(8) could enter into
an endless loop. The strange thing is, that we can call jls(8) while
the other one is in loop and it will succeed - SYSCTL_OUT() will
not return ENOMEM there.

Maybe SYSCTL_OUT() returns first ENOMEM, because there is no memory,
but is marking some memory range as wired even on failure and another
SYSCTL_OUT() calls are not going to succeed, because process exceeds
limit of wired memory? ENOVMCLUE.

Anyway. Fix jls(8) to ignore ENOMEM and retry only 4 times.

Submitted by:	Niklas Saers
PR:		kern/79245
MFC after:	3 days

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