Audit and fix classes in java.io for cases where close may fail

7015589 concerns the question as to the state of a resource in the event that its close method fails (by throwing an exception). The changes for 7015589 add an advisory note to java.lang.AutoCloseable and java.io.Closeable and fix a couple of classes, including BufferedReader and BufferedWriter.
 
There is further work that can be done on this issue. In particular BufferedOutputStream, PushbackReader and maybe others need to be checked to see how the behave when closing the underlying stream fails.