HDFS-14175. EC: Native XOR decoder should reset the output buffer before using it. Contributed by Ayush Saxena.

hadoop-common-project/hadoop-common/src/main/native/src/org/apache/hadoop/io/erasurecode/jni_xor_decoder.c

@@ -66,6 +66,8 @@ Java_org_apache_hadoop_io_erasurecode_rawcoder_NativeXORRawDecoder_decodeImpl(
       numDataUnits + numParityUnits);
   getOutputs(env, outputs, outputOffsets, xorDecoder->outputs, numParityUnits);
 
+  memset(xorDecoder->outputs[0], 0, chunkSize);
+
   for (i = 0; i < numDataUnits + numParityUnits; i++) {
     if (xorDecoder->inputs[i] == NULL) {
       continue;