test/read-write: work on 4kb blocksize devices

For some tests, we chop the iovec in two. Since the iovec is 4k in
size, this fails on devices that are actually using 4k block sizes.

Just bump the iovec size to 8k, then it'll work fine on 4k devices.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

test/read-write.c

@@ -16,8 +16,8 @@
 #include "helpers.h"
 #include "liburing.h"
 
-#define FILE_SIZE	(128 * 1024)
-#define BS		4096
+#define FILE_SIZE	(256 * 1024)
+#define BS		8192
 #define BUFFERS		(FILE_SIZE / BS)
 
 static struct iovec *vecs;