tests: Clean up includes

Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>
diff --git a/tests/test-string-input-visitor.c b/tests/test-string-input-visitor.c
index d99498d..4b48ec2 100644
--- a/tests/test-string-input-visitor.c
+++ b/tests/test-string-input-visitor.c
@@ -10,8 +10,8 @@
  * See the COPYING file in the top-level directory.
  */
 
+#include "qemu/osdep.h"
 #include <glib.h>
-#include <stdarg.h>
 
 #include "qemu-common.h"
 #include "qapi/string-input-visitor.h"