Update network_test example for Ethos-U (#416)

Change path to person detect model header file from example directory to
where it is downloaded.

tensorflow/lite/micro/examples/network_tester/network_tester_test.cc

@@ -24,8 +24,8 @@ limitations under the License.
 #include "tensorflow/lite/schema/schema_generated.h"
 
 #ifdef ETHOS_U
-#include "tensorflow/lite/micro/examples/person_detection/person_detect_model_data.h"
 #include "tensorflow/lite/micro/examples/person_detection/person_image_data.h"
+#include "tensorflow/lite/micro/tools/make/downloads/person_model_int8/person_detect_model_data.h"
 #endif
 
 #ifndef TENSOR_ARENA_SIZE

tensorflow/lite/micro/tools/make/ext_libs/person_detection_int8_vela_convert.sh

@@ -72,7 +72,7 @@ if [ ! -f ${CONVERTED_PERSON_MODEL_INT8} ]; then
 
   # Convert .tflite back to C array.
   echo "// This file is generated by $0." > ${CONVERTED_PERSON_MODEL_INT8}
-  echo '#include "tensorflow/lite/micro/examples/person_detection/person_detect_model_data.h"' >> \
+  echo '#include "tensorflow/lite/micro/tools/make/downloads/person_model_int8/person_detect_model_data.h"' >> \
        ${CONVERTED_PERSON_MODEL_INT8}
   echo -n "const " >> ${CONVERTED_PERSON_MODEL_INT8}
   xxd -i ${DOWNLOADED_PERSON_MODEL_INT8_PATH}/person_detect_vela.tflite >> \