The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/autotest/+/f5321f056459ea0073df92983a1daebe425875d4

commit f5321f056459ea0073df92983a1daebe425875d4
Author: Matt Mallett <mattmallett@chromium.org>
Date: Sat Feb 24 03:31:19 2018

[moblab] Run dut ssh test in parallel

The Manage DUTs page becomes slow with many DUTs connected, as
it checks each connected DUT for SSH connectivity in sequence.
This change has the checks run in parallel subprocesses and
provides a good speedup.

Also updated some messaging on UI for DUTs that couldn't be
reached by SSH, to make it clear what the problem is.

BUG= chromium:815275 , chromium:814425 
TEST=Added unit test for parallel test execution logic, and tested
functionality on local device with 24 connected DUTs.

Change-Id: Id087f02e9a5bf20e06cd536642164c356c747b74
Reviewed-on: https://chromium-review.googlesource.com/935881
Commit-Ready: Matt Mallett <mattmallett@chromium.org>
Tested-by: Matt Mallett <mattmallett@chromium.org>
Reviewed-by: Keith Haddow <haddowk@chromium.org>

[modify] https://crrev.com/f5321f056459ea0073df92983a1daebe425875d4/frontend/afe/moblab_rpc_interface_unittest.py
[modify] https://crrev.com/f5321f056459ea0073df92983a1daebe425875d4/frontend/afe/moblab_rpc_interface.py
[modify] https://crrev.com/f5321f056459ea0073df92983a1daebe425875d4/frontend/client/src/autotest/moblab/DutManagementView.java