tests: Add missing #includes to array-test

These are needed to get `SIZE_WIDTH` from libc. The tests which used
`SIZE_WIDTH` were previously effectively dead code. Spotted by
`-Wundef`.

Signed-off-by: Philip Withnall <pwithnall@gnome.org>

glib/tests/array-test.c

@@ -26,6 +26,8 @@
 
 #undef G_DISABLE_ASSERT
 
+#include <limits.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>