Turn v8_enable_shared_ro_heap on

[ry]

We want to be inline with what default chrome configurations are using to reduce technical debt https://github.com/denoland/rusty_v8/blob/ca83ce53bad172cd1b5f1fcfbe18cb936cbb3b7f/.gn#L48-L52

Problem: there are two snapshots in deno, the main runtime one, and the tsc one. How can we turn this on and also handle both of those? maybe don't snapshot tsc?

[mmastrac]

We might be able to fork before starting the snapshots which might allow us to use two snapshots side-by-side (just not in the same process). The benefit here would likely be a drastic memory reduction for the workers.