Update cpp/ql/test/query-tests/Security/CWE/CWE-119/semmle/tests/tests.cpp

Co-authored-by: Geoffrey White <40627776+geoffw0@users.noreply.github.com>

Author: MathiasVP

cpp/ql/test/query-tests/Security/CWE/CWE-119/semmle/tests/tests.cpp

@@ -713,7 +713,7 @@ struct HasSomeFields {
 	};
 
 	void test34() {
-		memset(&c, 0, sizeof(HasSomeFields) - offsetof(HasSomeFields, b)); // BAD
+		memset(&b, 0, sizeof(HasSomeFields) - offsetof(HasSomeFields, a)); // BAD
 	};
 
 	void test35() {