MFC r277278:
MFC r277278:

r277278 (by ngie):

  Fix lib/libthr/tests/detach_test

  - Eliminate race with liberal use of sleep(3) [1]
  - Fix NetBSD-specific implementation way of testing result from pthread_cancel
    by testing with `td` instead of `NULL` [2]

  PR: 196738 [1]
  PR: 191906 [2]

  Sponsored by: EMC / Isilon Storage Division

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase