DataHandle: simplify writeUTF method

Now it leans on the Java standard library (indirectly).

Author: ctrueden

src/main/java/org/scijava/io/handle/DataHandle.java

@@ -653,9 +653,7 @@ default void writeChars(final String s) throws IOException {
 
 	@Override
 	default void writeUTF(final String str) throws IOException {
-		final byte[] b = str.getBytes("UTF-8");
-		writeShort(b.length);
-		write(b);
+		DataHandles.writeUTF(str, this);
 	}
 
 }