Test reading mip levels with textureLoad and 2d textures. (#4157)

This line is only missing from the 2d version.
Without it only level 0 is read.

src/webgpu/shader/execution/expression/call/builtin/textureLoad.spec.ts

@@ -215,6 +215,7 @@ Parameters:
     const calls: TextureCall<vec2>[] = generateTextureBuiltinInputs2D(50, {
       method: samplePoints,
       descriptor,
+      mipLevel: { num: texture.mipLevelCount, type: L },
       hashInputs: [stage, format, samplePoints, C, L],
     }).map(({ coords, mipLevel }) => {
       return {