TIKA-817: (PPT/PPTX) Missing date/time in text content

Fix test failure on Windows where Java's built-in XML serializer would produce different line endings than on Mac/Unix environments

git-svn-id: https://svn.apache.org/repos/asf/tika/trunk@1537803 13f79535-47bb-0310-9956-ffa450edef68