Remove optimization scaffolding, re-visit in future issue.

[femtomc]

@tshort let's take out optimization interception for now.

This is likely to rapidly change (e.g. failing now on nightly because getfield_elim_pass! has been removed) with the escape analysis work in CC, so maybe we fallback on the default optimization pipeline, and re-enable things in the future.

[tshort]

Looks like it's a net negative on tests which suggests parts of optimization are needed.

[femtomc]

@tshort this should just be running Core.Compiler.optimize without modification, so this confuses me.