Move from inttypes.h to stdint.h

Some toolchains do not have inttypes.h, and we only need stdint.h which is a
subset of it.
diff --git a/tests/suites/helpers.function b/tests/suites/helpers.function
index b9f01ad..ecb5f15 100644
--- a/tests/suites/helpers.function
+++ b/tests/suites/helpers.function
@@ -16,7 +16,7 @@
 #include <basetsd.h>
 typedef UINT32 uint32_t;
 #else
-#include <inttypes.h>
+#include <stdint.h>
 #endif
 
 #include <stdio.h>