Just creating this to track it. We already compile the bundles with GCC simple mode. There's a bunch of things that will break in advanced mode but we're gradually moving closer to being able to do this.

I think #9955 is a prerequisite since otherwise we can never be sure we're still being correct. Landed!

Open question is if we can still keep DevTools working. I wonder if Fiber could be an array with fixed indexes and then we wouldn't need any "sourcemapping".