[BUG] Bugs of Tag Maintain and Property Cache Strategy in Group Operator

[BingqingLyu]

Describe the bug

Two bugs in group() in IR-Core:

1. tag maintain in group operator.
   An example is g.V().group().by(values("name").as("a")).select("a"), which output the following bug:
   

2. identifying what properties should be carried in advance.
   An example is g.V().group().by(outE().count()).by("name"), where "name" should be cached in the source operator g.V(), otherwise, we could not get property of "name" locally after grouping.
   Expected behavior: IR-Core should Identify "name" as a property that should be saved in the SourceOperator.

[BingqingLyu]

Have been fixed in #1847