scripting: fix array copy and, use System.arraycopy

Change-Id: If8addcc5d95f610ade404e62e4a2a775319e9ff3
Reviewed-on: https://gerrit.libreoffice.org/11354
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>

scripting/java/com/sun/star/script/framework/io/XOutputStreamWrapper.java

@@ -71,10 +71,7 @@ public class XOutputStreamWrapper extends OutputStream {
                 throw new java.io.IOException( "Stream is null" );
             }
             byte[] bytes = new byte[len];
-            for ( int i=off; i< off+len; i++ )
-            {
-                bytes[i] = b[i];
-            }
+            System.arraycopy(b, off, bytes, 0, len);
             try
             {
                 m_xOutputStream.writeBytes(bytes);