Add luci-go's isolate tool, downloaded via runhooks.

R=vadimsh@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1154633003

Cr-Original-Commit-Position: refs/heads/master@{#331184}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 4fbba012ab94bf81393095e6e3a55a6134c4957d
3 files changed
tree: 0c38fa792d7d2630cfec69582938f6f2f5ed25b8
  1. linux64/
  2. mac64/
  3. win64/