fix computation for localToWorld

Change-Id: I962f47dce685a938f6ec9f7fbbb79c34ea9b3c4b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/282677
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Reed <reed@google.com>

samplecode/Sample3D.cpp

@@ -103,7 +103,7 @@ public:
     SkM44 localToWorld(SkCanvas* canvas) {
         SkM44 camera;
         SkAssertResult(canvas->findMarkedCTM(kCameraID, &camera));
-        return inv(canvas->getLocalToDevice()) * camera;
+        return inv(camera) * canvas->getLocalToDevice();
     }
 };