[test][regression cases][external]add external table p2 regression cases according doris1.2 docs 20230105

[zhangguoqiang666]

Proposed changes

Problem summary

Describe your changes.
add external table p2 regression cases according doris1.2 docs

Checklist(Required)

1. Does it affect the original behavior:
   • No
2. Has unit tests been added:
   • No Need
3. Has document been added or modified:
   • No Need
4. Does it need to update dependencies:
   • No
5. Are there any changes that cannot be rolled back:
   • No

Further comments

If this is a relatively large or complex change, kick off the discussion at dev@doris.apache.org by explaining why you chose the solution you did and what alternatives you considered, etc...

[dataroaring]

LGTM