constant time test: include our internal/numbers.h rather than limits.h

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1856)
diff --git a/test/constant_time_test.c b/test/constant_time_test.c
index 41587e2..e53a73b 100644
--- a/test/constant_time_test.c
+++ b/test/constant_time_test.c
@@ -9,12 +9,12 @@
 
 #include "internal/constant_time_locl.h"
 #include "e_os.h"
-#include <openssl/e_os2.h>
 
-#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 
+#include "internal/numbers.h"
+
 static const unsigned int CONSTTIME_TRUE = (unsigned)(~0);
 static const unsigned int CONSTTIME_FALSE = 0;
 static const unsigned char CONSTTIME_TRUE_8 = 0xff;