Skip must use this.read() and not in.read() - Thanks, Adam, for catching this.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@271612 13f79535-47bb-0310-9956-ffa450edef68

proposal/sandbox/filterreaders/src/main/org/apache/tools/ant/filters/BaseFilterReader.java

@@ -141,7 +141,7 @@ public abstract class BaseFilterReader
         }
 
         for (long i = 0; i < n; i++) {
-            if (in.read() == -1) {
+            if (read() == -1) {
                 return i;
             }
         }