1145: Fix#1099, plug self type type parameters in infer_path_expr r=flodiebold a=edwin0cheng
As discussed in #1099, this PR try to "plug" a `self type` type parameters in `infer_path_expr`.
All the cases in 1099 was fixed and tested.
And luckily, this PR fixed bug #1030 again and make the test output correct.
Co-authored-by: Edwin Cheng <edwin0cheng@gmail.com>