3121: Do not add imports before inner attributes r=matklad a=SomeoneToIgnore Current `insert_use_statement` function adds imports before inner attributes which results in compiler errors: <img width="1440" alt="image" src="https://user-images.githubusercontent.com/2690773/74344019-a3749500-4db4-11ea-9d88-f71e903e795a.png"> Co-authored-by: Kirill Bulatov <mail4score@gmail.com>