GitLab

This reverts commit 6bb055be.

Reason for revert: P0 bug https://crbug.com/865882

Original change's description:
> tools/luci-go: remove old way of mapping isolate
> 
> It's now only mapped via CIPD, which is the right solution going forward.
> 
> Bug: 851596,865541
> Change-Id: I25ddd0e059c818fafbc5587b06ff35b6c733a16e
> Reviewed-on: https://chromium-review.googlesource.com/1143448
> Commit-Queue: Marc-Antoine Ruel <maruel@chromium.org>
> Reviewed-by: John Budorick <jbudorick@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#576550}

TBR=maruel@chromium.org,tandrii@chromium.org,jbudorick@chromium.org

Change-Id: I2d432e9c80379c41e22b7a1cfdb4ea3f54586baa
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 851596, 865541
Reviewed-on: https://chromium-review.googlesource.com/1145020Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Commit-Queue: Sergiy Byelozyorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576823}