Moving eob array to the encoder.

In the decoder we don't need to save eobs, we can pass eob as an argument.
That's why removing eob arrays from VP9Decompressor and TileWorkerData,
and moving eob pointer from macroblockd_plane to macroblock_plane.

Change-Id: I8eb919acc837acfb3abdd8319af63d1bbca8217a