Reason for revert:
These bots are now fully functional
Original issue's description:
> CQ: Remove ARM64 trybots until toolchain issues are resolved.
>
> BUG=webrtc:7024
> TBR=oprypin@webrtc.org
>
> Review-Url: https://codereview.webrtc.org/2776393005 .
> Cr-Commit-Position: refs/heads/master@{#17447}
> Committed: 2103f8e59b
TBR=oprypin@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7024
Review-Url: https://codereview.webrtc.org/2783003002
Cr-Commit-Position: refs/heads/master@{#17455}