Revert "Handle NULL buffer when discarding rows"

This reverts commit 922c23a.

since this change has issues on mac14 and windows.

Author: dpiparo

graf2d/asimage/src/libAfterImage/libjpeg/jquant1.c

@@ -528,10 +528,6 @@ quantize_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
   JDIMENSION col;
   JDIMENSION width = cinfo->output_width;
 
-  if (output_buf == NULL && num_rows) {
-    ERREXIT(cinfo, JERR_BAD_PARAM);
-  }
-
   for (row = 0; row < num_rows; row++) {
     /* Initialize output values to 0 so can process components separately */
     jzero_far((void FAR *) output_buf[row],