Disables perf graphs from stats.lua. They are relatively expensive to
render, causes a lot of memory to be used for caches which are never
reused because graph is rarely the same. And most importantly those
graphs are not that useful beyond quick visual inspection of jitter.
Can be enable in script-opt if needed. Cache graph is left enabled,
because it shows if cache readhead grows or not nicely.
Kacper Michajłow