Debug tool to verify the correctness of erasure coding on file

Block data in erasure coded block group may corrupt and the block meta (checksum) is unable to discover the corruption in some cases such as EC reconstruction, related issues are:  HDFS-14768, HDFS-15186, HDFS-15240.

In addition to HDFS-15759, there needs a tool to check erasure coded file whether any block group has data corruption in case of other conditions rather than EC reconstruction, or the feature HDFS-15759(validation during EC reconstruction) is not open(which is close by default now).