Revert of Android: Add field trial for Intel HW Vp8 encoder (patchset #1 id:1 of https://codereview.webrtc.org/2614373004/ )

Reason for revert:
Breaks external test code.

Original issue's description:
> Android: Add field trial for Intel HW Vp8 encoder
>
> Also enable Intel HW Vp8 encoder by default in AppRTCMobile.
>
> BUG=webrtc:6683
>
> Review-Url: https://codereview.webrtc.org/2614373004
> Cr-Commit-Position: refs/heads/master@{#16002}
> Committed: https://chromium.googlesource.com/external/webrtc/+/cecf86e9b0ba41c35eda360ae24b17b333ae1977

TBR=sakal@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6683

Review-Url: https://codereview.webrtc.org/2624143002
Cr-Commit-Position: refs/heads/master@{#16005}