* Introduce Agent-Test-Tool suite

* rename term

* Remove the local span and exit span register mechanism in Java agent scenario.

* Fix config, plugin, and document, as exit span is not required register anymore.

* Try to fix the test case expected data due to no register for exit span.

* Fix toolkit case.

* Remove exit span from plugin test framework document.

* Update protocol, FAQ, and CHANGELOG documents to highlight this change.

* Fix NPE when no entry span in the whole segment. Set endpoint to null in segment entity.

* Fix the snapshot and add inexistence operation name id.

* Fix several async cases.

* Fix undertow test case.

* Fix wrong error log name.

* Keep name consistent with 6.x concepts.

* Try to fix 3 async scenarios.

* Fix okhttp case.

* Fix Spring Async case.

* Fix another NPE

* Fix NPE when first span has no endpoint id when it is local or exit span.

* Still fill first operation name when no endpoint id.

* Add postgresql agent sql query param show

* Modify plugin test run.sh script parameter error

* shell fun error, delete ()

* delete space line

* [test/plugin] immigrate postgresql scenario

* add licene

* format expectedData.yaml & update support-version.list

* change workload from 3 to 1

* add startup.sh

* update startup.sh

* Add verify health-check segment

* remove health-check segment

* update code. 1. context is not effective; 2.format code. 3.change log to slf4j;

* update expectedData.yaml & change log to log4j2

* Add stage case count

* add immigrate postgresql-9.4-scenario

* repair module name & package name

* repair all postgresql-9.4 to postgresql-above9.4.1207

* change module name to postgresql-above9.4.1207

* change stage name