8196787: (ch) Moving network channels to use j.u.c locks

[Pavel Rappo]

> On 5 Feb 2018, at 17:04, Alan Bateman <Alan.Bateman at oracle.com> wrote:
> 
> The async close of these Pipe source/sink classes has been incorrect since 1.4. It will be fixed in a follow-up patch that re-works the async close where it will be clearer why the isOpen must be checked while holding the readLock.
> 
> -Alan

I'm fine with the changes. Thanks.