RFR 8009581: Xpathexception does not honor initcause()

[Jason Mehrens]

>> You can still generate a ISE inside readObject by performing "new XPathException(new Exception()).initCause(null)" in the old code and then reading that in the new patch. In the new code that line would fail fast.
>
> So what should the result of this be given that the original exception
> has an inconsistent state (two 'causes')?
>

Maybe catch ISE and throw InvalidObjectException or StreamCorruptedException?

Jason