This hardens the wasb and abfs output streams' resilience to being invoked
in/after close().
wasb:
Explicity raise IOEs on operations invoked after close,
rather than implicitly raise NPEs.
This ensures that invocations which catch and swallow IOEs will perform as
expected.
abfs:
When rethrowing an IOException in the close() call, explicitly wrap it
with a new instance of the same subclass.
This is needed to handle failures in try-with-resources clauses, where
any exception in closed() is added as a suppressed exception to the one
thrown in the try {} clause
*and you cannot attach the same exception to itself*
Contributed by Steve Loughran.
Change-Id: Ic44b494ff5da332b47d6c198ceb67b965d34dd1b
17aa8f6764