[pizlonator]

When JITing Java, the main profiling inputs are for call devirtualization. That has a lot of randomness, but it's confined to just those callsites where the JIT would need profiling to devirtualize.

When JITing JavaScript, every single fundamental operation has profiling. Adding stuff has multiple bits of profiling. Every field access. Every array access. Like, basically everything, including also callsites. And without that profiling, the JS JIT can't do squat, so it depends entirely on that profiling. So the randomness due to profiling has a much more extreme effect on what the compiler can even do.