MFC 236768,252209,253047:
Several improvements to rmlock(9).  Many of these are based on patches
provided by Isilon.
- Add an rm_assert() supporting various lock assertions similar to other
  locking primitives.  Because rmlocks track readers the assertions are
  always fully accurate unlike rw_assert() and sx_assert().
- Flesh out the lock class methods for rmlocks to support sleeping via
  condvars and rm_sleep() (but only while holding write locks), rmlock
  details in 'show lock' in DDB, and the lc_owner method used by
  dtrace.
- Add an internal destroyed cookie so that API functions can assert
  that an rmlock is not destroyed.
- Make use of rm_assert() to add various assertions to the API (e.g.
  to assert locks are held when an unlock routine is called).
- Give RM_SLEEPABLE locks their own lock class and always use the
  rmlock's own lock_object with WITNESS.
- Various updates to the manpage.
MFC	r250574, r250812, r253725;

DTrace: option for time-ordered output

Merge changes from illumos:

3021 option for time-ordered output from dtrace(1M)
3022 DTrace: keys should not affect the sort order when sorting by value
3023 it should be possible to dereference dynamic variables
3024 D integer narrowing needs some work
3025 register leak in D code generation

This brings yet another feature implemented in upstream DTrace.
A complete description is available here:
http://dtrace.org/blogs/ahl/2012/07/28/my-new-dtrace-favorite/

This change bumps the DT_VERS_* number to 1.9.1 in
accordance to what is done in illumos.

Special thanks to Mark Johnston for fixes and testing.

Illumos Revisions:	13758:23432da34147

Reference:
https://www.illumos.org/issues/3021
https://www.illumos.org/issues/3022
https://www.illumos.org/issues/3023
https://www.illumos.org/issues/3024
https://www.illumos.org/issues/3025
https://www.illumos.org/issues/1694

Obtained from:	Illumos