C++: Move qhelp.

cpp/ql/src/Critical/DoubleFreeBad.cpp

@@ -0,0 +1,10 @@
+int* f() {
+	int *buff = malloc(SIZE*sizeof(int));
+	do_stuff(buff);
+	free(buff);
+	int *new_buffer = malloc(SIZE*sizeof(int));
+	free(buff); // BAD: If new_buffer is assigned the same address as buff,
+              // the memory allocator will free the new buffer memory region,
+              // leading to use-after-free problems and memory corruption.
+	return new_buffer;
+}