FreeBSD_HEAD_i386 - Build #3600 - Fixed

FreeBSD_HEAD_i386 - Build #3600 - Fixed:

Build information: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_i386/3600/
Full change log: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_i386/3600/changes
Full build log: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_i386/3600/console

Change summaries:

302921 by jhb:
Rename PTRACE_SYSCALL to LINUX_PTRACE_SYSCALL.

Suggested by:	kib

302920 by bapt:
Add a regression test to make sure the Russian collation is actually working

when importing collation support from Dragonfly/Illumos amdmi3_at_ tested the
collation branch and reported an issue with Russian collation. John Marino fixed
the issue in Dragonfly and I merged it back to FreeBSD.

Now that Illumos is working on merging our fixes they (Lauri Tirkkonen) found
issues with the commit that fixes the russian collation in UTF-8 that resulted
in a crash with strxfrm(3) and the ISO-8859-5 locale (fixed in FreeBSD r302916).
This small test was written to ensure we do not bring back the old issue with
russian collation while fixing the other issue.

302919 by kib:
In ptrace_vm_entry(), do not call vmspace_free() while owning a vm
object lock.

The vmspace_free() operations might need to lock map, object etc on
last dereference.  Postpone the free until object's inspection is
done.

Reported and tested by:	will
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week

302918 by bapt:
Add a regression test about the crash with strxfrm and ISO8859-5 locales