@Override
    public long getNormalizerTargetRegionSize() {
      long target_region_size =
        getOrDefault(NORMALIZER_TARGET_REGION_SIZE_MB_KEY, Long::valueOf, Long.valueOf(-1));
      return target_region_size == Long.valueOf(-1)
        ? getOrDefault(NORMALIZER_TARGET_REGION_SIZE_KEY, Long::valueOf, Long.valueOf(-1))
        : target_region_size;
    }
Check if there is the target region size. If so, the normalize plan will be calculated based
on the target region size.
@return target region size after normalize done
hbase-client/src/main/java/org/apache/hadoop/hbase/client/TableDescriptorBuilder.java