fix(select): don't support binding to select[multiple]

changing the type of select box from single to multiple or the other way around
at runtime is currently not supported and the two-way binding does odd stuff
when such situation happens.

we might eventually support this, but for now we are just going to not allow
binding to select[multiple] to prevent people from relying on something that
doesn't work.

BREAKING CHANGE: binding to select[multiple] directly or via ngMultiple (ng-multiple)
directive is not supported. This feature never worked with two-way data-binding,
so it's not expected that anybody actually depends on it.

Closes #3230