Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r253996,253997: opensolaris code: translate INVARIANTS to DEBUG and ZFS_DEBUG

Please note that support for compiling ZFS into a kernel is not in this
branch as of now.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Stripped '32' suffix from linux systrace module name on i386.

Approved by: avg

add DTrace systrace support for linux32 and freebsd32 on amd64 syscalls

Add systrace_linux32 and systrace_freebsd32 modules which provide
support for tracing compat system calls in addition to native system
call tracing provided by systrace module.

Provided that all the systrace modules are loaded now you can select
what syscalls to trace in the following manner:

syscall::xxx:yyy - work on all system calls that match the specification
syscall:freebsd:xxx:yyy - only native system calls
syscall:linux32:xxx:yyy - linux32 compat system calls
syscall:freebsd32:xxx:yyy - freebsd32 compat system calls on amd64

PR: kern/152822
Submitted by: Artem Belevich <fbsdlist@src.cx>
Reviewed by: jhb (earlier version)
MFC after: 3 weeks