reset node

## Issue Description

I use sentinel to implement resiliency for by web services.
I found it is very difficult to write multiple tests for the same resource with different rules because sentinel keeps context from the previous test.
For example sentinel_block_requests_total is already not null when the second test is running.

How to reset/clean all sentinel counts before each test using public API?
I use the following code:
ClusterNode node = ClusterBuilderSlot.getClusterNode(nodeName);
if (node!=null) {
node.reset();
node.metrics().clear();
node.metrics().values().clear();
}
But it does not help
I still see that node.totalExceptiopnI() is not set to 0

### Describe what happened (or what feature you want)

I need to reset all counters to null

### Describe what you expected to happen

### How to reproduce it (as minimally and precisely as possible)

1.
2.
3.

### Tell us your environment

java web services

### Anything else we need to know?

Start by tracing ClusterBuilderSlot.getClusterNode(nodeName), ClusterNode.reset(), and the node.metrics() calls described in the issue. Check how sentinel_block_requests_total and totalExceptiopnI are maintained, then determine whether the public API can reset them between tests. Done means a reproducible test shows all counters reset to zero before the next rule set runs.

Written by the indexing model from the issue text.