Add (void) when st is unused

This is to get rid of the GCC warning:
"warning: unused variable ‘st’ [-Wunused-variable]"
diff --git a/tests/90-cond-int-type-OK.asn1.-Pfwide-types b/tests/90-cond-int-type-OK.asn1.-Pfwide-types
index f170d99..30633fd 100644
--- a/tests/90-cond-int-type-OK.asn1.-Pfwide-types
+++ b/tests/90-cond-int-type-OK.asn1.-Pfwide-types
@@ -159,6 +159,7 @@
 	
 	
 	if(1 /* No applicable constraints whatsoever */) {
+		(void)st; /* Unused variable */
 		/* Nothing is here. See below */
 	}