OS-7753 THREAD_KPRI_RELEASE does nothing of the sort
Reviewed by: Bryan Cantrill <bryan@joyent.com>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>

*** 24,33 ****
--- 24,34 ----
   * Use is subject to license terms.
   */
  
  /*
   * Copyright (c) 2012 by Delphix. All rights reserved.
+  * Copyright 2019 Joyent, Inc.
   */
  
  #include <sys/thread.h>
  #include <sys/proc.h>
  #include <sys/debug.h>
*** 550,560 ****
  
          cancel_pending = schedctl_cancel_pending();
          lwp->lwp_asleep = 1;
          lwp->lwp_sysabort = 0;
          thread_lock(t);
-         t->t_kpri_req = 0;      /* don't need kernel priority */
          cv_block_sig(t, (condvar_impl_t *)cvp);
          /* I can be swapped now */
          curthread->t_schedflag &= ~TS_DONT_SWAP;
          thread_unlock_nopreempt(t);
          mutex_exit(mp);
--- 551,560 ----
*** 761,772 ****
   * Generally, cv_timedwait_sig_hrtime() should be used instead of this
   * routine.  It waits based on hrtime rather than wall-clock time and therefore
   * does not need to deal with the time changing.
   */
  int
! cv_waituntil_sig(kcondvar_t *cvp, kmutex_t *mp,
!         timestruc_t *when, int timecheck)
  {
          timestruc_t now;
          timestruc_t delta;
          hrtime_t interval;
          int rval;
--- 761,772 ----
   * Generally, cv_timedwait_sig_hrtime() should be used instead of this
   * routine.  It waits based on hrtime rather than wall-clock time and therefore
   * does not need to deal with the time changing.
   */
  int
! cv_waituntil_sig(kcondvar_t *cvp, kmutex_t *mp, timestruc_t *when,
!     int timecheck)
  {
          timestruc_t now;
          timestruc_t delta;
          hrtime_t interval;
          int rval;