Don't derive grammar in CORE.setting.

Fixes an issue reported by donaldh++ where we were declaring a new op
inside of the setting. This caused a new grammar to be derived, which
in turn ended up including fresh NFAs and an entire copy of the source
to end up the file too! Fixing this shaves ~6MB off CORE.setting size,
about 14MB off base memory, and decreases startup time too.