* HDFS-16586. Purge FsDatasetAsyncDiskService threadgroup; it causes BPServiceActor IllegalThreadStateException 'fatal exception and exit'
Remove the ThreadGroup used by executor factories; they are unused
and ThreadGroups auto-destroy when their Thread-member count goes to zero.
This behavior is incompatible with the configuration we have on the per-volume
executor which is set to let all threads die if no use inside the
keepalive time.
Signed-off-by: Hexiaoqiao <hexiaoqiao@apache.org>
5ab747222b