Move stat_io_bytes/time to thread_data

Anything that isn't needed to sum/show thread stats should not be
in struct thread_stat.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fio.h b/fio.h
index b0307df..12b3e3d 100644
--- a/fio.h
+++ b/fio.h
@@ -189,9 +189,6 @@
 	struct io_stat lat_stat[2];		/* total latency */
 	struct io_stat bw_stat[2];		/* bandwidth stats */
 
-	uint64_t stat_io_bytes[2];
-	struct timeval stat_sample_time[2];
-
 	/*
 	 * fio system usage accounting
 	 */
@@ -432,6 +429,9 @@
 	struct io_log *lat_log;
 	struct io_log *bw_log;
 
+	uint64_t stat_io_bytes[2];
+	struct timeval stat_sample_time[2];
+
 	struct fio_file **files;
 	unsigned int files_size;
 	unsigned int files_index;