RFR JDK-8034802: (zipfs) newFileSystem throws UOE when the zip file is located in a custom file system

[Xueming Shen]

Hi

Please help review the change for JDK-8034802.
issue: https://bugs.openjdk.java.net/browse/JDK-8034802
webrev: http://cr.openjdk.java.net/~sherman/8034802/webrev

One of the reasons that the implementation works this way is that I 
didn't have a
complete SeekableByteChannel support (mainly the position(...)) from 
newByteChannel()
back then (so you really can't get a ZipFileSystem from a jar/zip file 
inside a zfs :-))

So this changeset also includes a ByteArrayChannel which implements SBC 
and has
better position()/position(int) support, and now we can have a zipfs 
from a zip file
inside a zipfs.

Thanks,
Sherman