9210 remove KMDB branch debugging support
9211 ::crregs could do with cr2/cr3 support
9209 ::ttrace should be able to filter by thread
Reviewed by: Patrick Mooney <patrick.mooney@joyent.com>

*** 22,32 ****
  /*
   * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  /*
!  * Copyright 2015 Joyent, Inc.
   * Copyright (c) 2014 by Delphix. All rights reserved.
   */
  
  /*
   * User Process Target
--- 22,32 ----
  /*
   * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  /*
!  * Copyright 2018 Joyent, Inc.
   * Copyright (c) 2014 by Delphix. All rights reserved.
   */
  
  /*
   * User Process Target
*** 4693,4703 ****
          pt_name_to_ctf,                         /* t_name_to_ctf */
          pt_status,                              /* t_status */
          pt_run,                                 /* t_run */
          pt_step,                                /* t_step */
          pt_step_out,                            /* t_step_out */
-         (int (*)()) mdb_tgt_notsup,             /* t_step_branch */
          pt_next,                                /* t_next */
          pt_continue,                            /* t_cont */
          pt_signal,                              /* t_signal */
          pt_add_vbrkpt,                          /* t_add_vbrkpt */
          pt_add_sbrkpt,                          /* t_add_sbrkpt */
--- 4693,4702 ----