Change the default XMLBeans version used for running to be 2.6, leave 2.3 for compiling the schemas (for maximum compatibility)

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1615780 13f79535-47bb-0310-9956-ffa450edef68
Before parsing an OOXML document, reset the xmlbeans sax parser to avoid the risk of getting one in an error state (due to XMLBEANS-512). Should be a minimal extra overhead pending a proper fix. Allows us to finish enabling the unit tests for #54764

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1615781 13f79535-47bb-0310-9956-ffa450edef68