lang: gapi, unification: Shutdown unification quickly when asked

This is a bit of a hack until we improve the GAPI a bit, but will let us
shut down type unification a bit faster if we want to interrupt a long
running operation. Hopefully our future algorthmic performance
improvements will obliviate the need for this to be a common issue.

lang/lang.go

@@ -232,6 +232,7 @@ func (obj *Lang) Init(ctx context.Context) error {
 		Debug:  obj.Debug,
 		Logf:   logf,
 	}
+	// NOTE: This is the "real" Unify that runs. (This is not for deploy.)
 	unifyErr := unifier.Unify(ctx)
 	obj.Logf("type unification took: %s", time.Since(timing))
 	if unifyErr != nil {