print to cerr for bad states in the test-main

offloading-cacher/main.cpp

@@ -65,7 +65,7 @@ void PerformAccessAndTest(double* src, const size_t size) {
         std::cout << "Caching did not affect data location." << std::endl;
     }
     else if (cached == nullptr) {
-        std::cout << "Got nullptr from cache." << std::endl;
+        std::cerr << "Got nullptr from cache." << std::endl;
     }
     else {
         std::cout << "Got different data location from cache." << std::endl;
@@ -75,7 +75,7 @@ void PerformAccessAndTest(double* src, const size_t size) {
         std::cout << "Cached data is correct." << std::endl;
     }
     else {
-        std::cout << "Cached data is wrong." << std::endl;
+        std::cerr << "Cached data is wrong." << std::endl;
     }
 }