We should switch the framework benchmarks to using -O2 for both dart2js and dart2wasm, and observe the effects in skia perf. This will help us determine if we can make -O2 the default in order to make sure the users get full soundness.

• Land -02 default switch in master (@eyebrowsoffire )
• Evaluate performance diff w/ DevTools
• Evaluate performance diff w/ 3rd parties (@kevmoo to coordinate)