Avoid unnecessary array fill after creation in PaletteBuilder

In the method 'com.sun.imageio.plugins.common.PaletteBuilder#buildPalette' a new array is created and then immediately filled with 'null'

        reduceList = new ColorNode[MAXLEVEL + 1];
        for (int i = 0; i < reduceList.length; i++) {
            reduceList[i] = null;
        }

It's redundant. Java guarantees that all elements of array are nulls anyway.