malloc() is already going to be randomized though for security reasons. The test just verifies that the randomization also leaves enough space for a realloc() t

malloc() is already going to be randomized though for security reasons. The test just verifies that the randomization also leaves enough space for a realloc() to be fast and efficient rather than having the randomization putting all of the malloc() calls into a very small area, thereby making realloc() always move the data to a new location.