A cleaner way to handle suffix inference for unary minus exprs.

This reverts commit 290206b1.

Forgot to add the actual native code, temporarily reverting.

The first benchmark shows about twice the throughput of the old system.

Related to issue #2657, but this is not a complete fix.

Incoming

Ports now are represented internally as classes.

Irritatingly, class dtors have a different type from resource
dtors (because class dtors have a self argument), and the monomorphic
case wasn't reflecting that. Fixed.