6867101: Path.checkAccess fails with sharing violation on special files such as pagefile.sys

[Alan Bateman]

Sherman - do you mind reviewing this one?

Applications on Windows periodically encounter system files such as 
those to support paging or hibernation that aren't intended to be 
accessed by regular applications. Attempts to access such files 
typically fails with a sharing violation, confusing convenience methods 
such as "exists" as they can't confirm the existence of the file. This 
patch adds a fallback to read the attributes via a directory search.
    http://cr.openjdk.java.net/~alanb/6867101/webrev.00/

Thanks,
Alan.