8220477: Channels.newWriter() does not close if underlying channel throws an IOException

[Brian Burkhalter]

For the issue [1] please review the proposed patch [2]. The change is to catch an IOException thrown by implClose() and mark the {en,de}coder as closed anyway. Lots of lines of test for a small change!

Thanks,

Brian

[1] https://bugs.openjdk.java.net/browse/JDK-8220477
[2] http://cr.openjdk.java.net/~bpb/8220477/webrev.00/