Actually, it's faster if I just do this now:
https://crrev.com/c/932364

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build/+/9b0f726bbc02a1cc858b7c3aa9dd66df2020e904

commit 9b0f726bbc02a1cc858b7c3aa9dd66df2020e904
Author: Michael Achenbach <machenbach@chromium.org>
Date: Thu Feb 22 22:06:47 2018

V8: Add mips64el tester

Also use streamlined swarming properties for both mips testers.

Bug:  814875 
Change-Id: I5e180b9aff88df787746f96f21bb88d6cf847c26
Reviewed-on: https://chromium-review.googlesource.com/932364
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>

[add] https://crrev.com/9b0f726bbc02a1cc858b7c3aa9dd66df2020e904/scripts/slave/recipes/v8.expected/full_client_v8_ports_V8_Linux___mips64el___sim.json
[modify] https://crrev.com/9b0f726bbc02a1cc858b7c3aa9dd66df2020e904/scripts/slave/v8/gatekeeper_v8_tree_closers.json
[modify] https://crrev.com/9b0f726bbc02a1cc858b7c3aa9dd66df2020e904/masters/master.client.v8.ports/slaves.cfg
[modify] https://crrev.com/9b0f726bbc02a1cc858b7c3aa9dd66df2020e904/scripts/slave/recipe_modules/v8/builders.py
[modify] https://crrev.com/9b0f726bbc02a1cc858b7c3aa9dd66df2020e904/scripts/slave/recipes/v8.expected/full_client_v8_ports_V8_Linux___mipsel___sim.json
[modify] https://crrev.com/9b0f726bbc02a1cc858b7c3aa9dd66df2020e904/scripts/slave/recipes/v8.expected/full_client_v8_ports_V8_Linux___mips64el___sim___builder.json
[modify] https://crrev.com/9b0f726bbc02a1cc858b7c3aa9dd66df2020e904/masters/master.client.v8.ports/master.cfg

Here's the bot:
https://build.chromium.org/p/client.v8.ports/builders/V8%20Linux%20-%20mips64el%20-%20sim

This was swift, thank you very much