x86 android: default on realtime-only
x86 android: default on realtime-only

Like the arm-based target, set realtime-only on by default.

BUG=webm:873

Change-Id: I2e04cfc43390953435e985716a25f32b8d4fadda

ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx