Several code using XWikiAttachmentContent#setContent(InputStream) or #getContentInputStream() are not closing the stream

In fact, it appears that all file input and output streams, not just AutoCloseInputStream, are eventually closed by the JDK when the stream becomes unreachable using FileCleanable. So I fear we're currently almost not noticing any missing file closing due to this as it probably needs very special load patterns with little GC pressure to trigger any limits due to this.