Test fixture doesn't need to be public

Author: garydgregory

src/test/java/org/apache/commons/io/channels/NonBlockingFileChannelProxy.java

@@ -25,7 +25,7 @@
 /**
  * Simulates a non-blocking file channel by returning 0 from reads every other call as allowed by {@link ReadableByteChannel} and {@link FileChannel}.
  */
-public class NonBlockingFileChannelProxy extends FileChannelProxy {
+class NonBlockingFileChannelProxy extends FileChannelProxy {
 
     boolean toggleRead0;