Upgrade agent-test-tools and polish dubbo plugin

[nisiyong]

• Upgrade skywalking-agent-test-tools
• Update docs and fix wrong spelling
• Relate Support collecting dubbo thread pool metrics #382
• Relate Support start with and end with skywalking-agent-test-tool#47

• Update the CHANGES log.

[wu-sheng]

@nisiyong It seems the tool change breaks.

[nisiyong]

@nisiyong It seems the tool change breaks.

I will take a look.

[nisiyong]

Finally, the agent-test-tools has fixed the prefix bug. And at the same time, I found start with or not blank couldn't use at the MeterItems tag value, because the MeterId will compare with the MeterItems tag value.

MeterId.java

public class MeterId {
    ...
    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        MeterId meterId = (MeterId) o;
        return Objects.equals(name, meterId.name) &&
            Objects.equals(tags, meterId.tags);
    }
}

So I am not going to change the dubbo thread pool name, but the agent-test-tools still support the new operators start with and end with in other cases.

[wu-sheng]

I am not very clear why eq works, but start with not?

[nisiyong]

I am not very clear why eq works, but start with not?

All the operator could work well at the expected value. But in the meter scenario, the test-tools will find the same meter first, then compare the meter value. The same meters must have the same tag-keys and the same tag-value, that's why MeterId#equals compare with tags and MeterId.Tag#equals compared with tag-key and tag-value.

[nisiyong]

The agent-test -tools repo URL and revision has be updated. All things are done, @wu-sheng please take a look.