* Ensure console mocks are reset after every test, without having to explicity do so.

* Graphcache: Wrap all `opts` validation in `if (process.env.NODE_ENV !== 'production')`.

* Graphcache: console.warn() if creating a store and updates has invalid mutations/subscriptions.

* Graphcache: console.warn() if creating a store with invalid resolvers.

* Graphcache: console.warn() if creating a store with invalid optimistic mutations.

* Graphcache: expand tests for query() and write().

* Graphcache: update changeset for new console.warn().