Fix TypeScript test for GridImageryProvider
Fix TypeScript test for GridImageryProvider

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