This PR mistakenly removed JIT enabling/disabling by preference:
https://github.com/servo/servo/pull/10342/files
Look for `get_pref`.
I'm putting the missing piece of code into the appropriate place in
script_runtime.rs
r? @KiChjang
Source-Repo: https://github.com/servo/servo
Source-Revision: bead9585000eed60394b20c7a8e3788284ea458a