test: REQUEST_FIXED_SIZE expression is always true comparing unsigned int to SIZE_MAX

`SIZE_MAX` is out of the range of `client->req_len` (unsigned int).
Compare `client->req_len` to `UINT_MAX` instead.

This fixes one of the Clang warnings as mentioned in #23.

Signed-off-by: Spxctre <[email protected]>

Author: onlyspxctre

test/misc.c

@@ -169,7 +169,7 @@ dix_request_fixed_size_overflow(ClientRec *client)
     xReq req = { 0 };
 
     client->req_len = req.length = 1;
-    REQUEST_FIXED_SIZE(req, SIZE_MAX);
+    REQUEST_FIXED_SIZE(req, UINT_MAX);
     return Success;
 }