Add mising path to ooxml-schemas which is necessary for building with latest JDK 16 ea-builds

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1882830 13f79535-47bb-0310-9956-ffa450edef68

build.xml

@@ -1273,6 +1273,7 @@ under the License.
                unless:true="${isJava8}">
             <compilerarg line="--patch-module org.apache.poi.stress=${integration.output.test.dir}"/>
             <modulepath>
+                <pathelement path="build/dist/maven/ooxml-schemas"/>
                 <pathelement path="build/dist/maven/poi"/>
                 <pathelement path="build/dist/maven/poi-ooxml"/>
                 <pathelement path="build/dist/maven/poi-scratchpad"/>