Fixes crash on B3DMs without batch tables
Fixes crash on B3DMs without batch tables

CesiumGS/cesium,CesiumGS/cesium,CesiumGS/cesium,likangning93/cesium,likangning93/cesium,likangning93/cesium,AnalyticalGraphicsInc/cesium,likangning93/cesium,CesiumGS/cesium,likangning93/cesium,AnalyticalGraphicsInc/cesium,CesiumGS/cesium