### What changes were proposed in this pull request?
Spark doesn't support aggregate functions with mixed outer and local references. This PR applies this check earlier to fail with a clear error message instead of some weird ones, and simplifies the related code in `SubExprUtils.getOuterReferences`. This PR also refines the error message a bit.
### Why are the changes needed?
better error message
### Does this PR introduce _any_ user-facing change?
no
### How was this patch tested?
updated tests
Closes#32503 from cloud-fan/try.
Authored-by: Wenchen Fan <wenchen@databricks.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
3b63f32601