GitLab

During that period of time, COMPUTERNAME in full environment printout is
listed as SWARM761-C4 instead of the real bot.

This CL collects bot name from multiple places and selects one as "BUILD***".

BUG=867155
TEST=manual
R=kbr@chromium.org
NOTRY=true

Change-Id: I5ffda633449ae869885643b3927dead9f8b58758
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1562894Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Zhenyao Mo <zmo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#649736}