reflect: add a secret method to ArrayOrSliceType. It was observed that the interface was generic enough that several other types implemented it too.
reflect: add a secret method to ArrayOrSliceType.
It was observed that the interface was generic enough
that several other types implemented it too.

Fixes issue 1530.

R=rsc
CC=golang-dev
http://codereview.appspot.com/4169063
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go