make IH.clearCache() public

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@466300 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/IntrospectionHelper.java

@@ -1321,7 +1321,7 @@ public final class IntrospectionHelper  {
     /**
      * Clears the static cache of on build finished.
      */
-    /*package private*/ static void clearCache() {
+    public static void clearCache() {
         HELPERS.clear();
     }