ConfigurationLoader needs to share context of execution during exception wrap

[romani]

detected at https://github.com/checkstyle/checkstyle/pull/11701/files

catch (final CheckstyleException ex) {
    // -@cs[IllegalInstantiation] SAXException is in the overriden
    // method signature
    throw new SAXException(ex);
}

should be something like:

catch (final CheckstyleException ex) {
    // -@cs[IllegalInstantiation] SAXException is in the overridden
    // method signature
    throw new SAXException("Exception during replacing values in property " + attributes.getValue(VALUE), ex);
}

Rationale: we need to share context of execution during exception wrap.
https://docs.oracle.com/javase/7/docs/api/org/xml/sax/SAXException.html#SAXException(java.lang.String,%20java.lang.Exception)