Revert of [release] Change blink trybot name on v8 roll CLs (patchset #1 id:1 of https://codereview.chromium.org/2185513002/ )

Reason for revert:
Revert,  because blink tryserver bot rename is reverted.

BUG=chromium:631448

Original issue's description:
> [release] Change blink trybot name on v8 roll CLs
>
> BUG=chromium:590036
> NOTRY=true
>
> Committed: https://crrev.com/a5fae1039409864295b42a6f33cef85ca9396bda
> Cr-Commit-Position: refs/heads/master@{#38041}

TBR=hablich@chromium.org,machenbach@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:590036

Review-Url: https://codereview.chromium.org/2186593003
Cr-Commit-Position: refs/heads/master@{#38062}