Refactoring Node2ObjectsMap, Node2PipelineMap, Node2ContainerMap

[Montura]

There is a base class org.apache.hadoop.hdds.scm.node.states.Node2ObjectsMap for Node2PipelineMap and Node2ContainerMap.

It is redundant because of:

1. Node2ContainerMap is used only in tests
2. Node2PipelineMap doesn't  need inheritance at all

Moreover Node2PipelineMap contains ConcurrentHashMap<UUID, Set<PipelineID>>and 2 synchronized methods:

• void addPipeline(Pipeline pipeline) -> compute if absent for concurrent hash map
• void removePipeline(Pipeline pipeline) -> compute if present for concurrent hash map

I suppose synchronized is redundant here for these two methods.

There is a proposed change:

1. Remove org.apache.hadoop.hdds.scm.node.states.Node2ObjectsMap class
2. Move Node2ContainerMap to tests
3. Don't use synchronized for Node2PipelineMap::addPipeline and Node2PipelineMap::removePipeline

[kerneltime]

Ref: #6303