This reverts commit ccfa4ca7.

Reason for revert: Infra supports this now.

Original change's description:
> [node] reset node checkout on v8 update
> 
> This is a temporary measure to get bots back in order.
> 
> Bug: chromium:860430
> 
> TBR=machenbach@chromium.org
> 
> Change-Id: I3275150f4bc5dfe8ab90984e15f8a1a469d70caf
> Reviewed-on: https://chromium-review.googlesource.com/1127166
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Commit-Queue: Yang Guo <yangguo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#54269}

TBR=machenbach@chromium.org,yangguo@chromium.org

Change-Id: I6a74ab702fd32b278caebb665be6868b4712dffb
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:860430
Reviewed-on: https://chromium-review.googlesource.com/1127721Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54287}