avoid extra Text nodes (ignoringBoundaryWhitespace) — our second SaxBuilder (jdom.kt) uses it for several years already without any regression

To avoid regressions, ignoringElementContentWhitespace is still false (our second SaxBuilder uses true, but... for not it is not safe (it is very sensitive area and better to turn it on later))

platform/util/src/com/intellij/openapi/util/JDOMUtil.java

@@ -246,6 +246,7 @@ public class JDOMUtil {
           return new InputSource(new CharArrayReader(ArrayUtil.EMPTY_CHAR_ARRAY));
         }
       });
+      saxBuilder.setIgnoringBoundaryWhitespace(true);
       ourSaxBuilder.set(new SoftReference<SAXBuilder>(saxBuilder));
     }
     return saxBuilder;