Go validator n steps (#124)

* Support runtime input.

* n steps

* add test case

* fix error

* delete buildSubGraphPlan not finish

* space indent

* modify code

* remove redundant line

Co-authored-by: William Chen <13495049+CPWstatic@users.noreply.github.com>
Co-authored-by: jimingquan <mingquan.ji@vesoft.com>
Co-authored-by: laura-ding <48548375+laura-ding@users.noreply.github.com>