Handle case where the JaCoCo zip file is available, but the extracted files are missing, not sure how that happens, but we see it on some CI machines...

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1815755 13f79535-47bb-0310-9956-ffa450edef68

build.xml

@@ -634,6 +634,9 @@ under the License.
                     <available file="${dsig.sl4j-api.jar}"/>
                     <available file="${main.commons-collections4.jar}"/>
                     <available file="${main.commons-math3.jar}"/>
+
+                    <!-- we had some CI failures when the extracted files for JaCoCo were missing somehow... -->
+                    <available file="${main.lib}/jacocoagent.jar"/>
                 </and>
                 <isset property="disconnected"/>
             </or>