[vector] Remove Vector.random/single/toList

[John Rose]

Looks good!

> On Oct 29, 2019, at 11:59 AM, Paul Sandoz <paul.sandoz at oracle.com> wrote:
> 
> Here is a patch to remove Vector.random/single/toList:
> 
>  http://cr.openjdk.java.net/~psandoz/panama/vector-remove-method/webrev/ <http://cr.openjdk.java.net/~psandoz/panama/vector-remove-method/webrev/>
> 
> I also fixed some typos.
> 
> Thanks,
> Paul.