fix: Pick correct columns in Sort Merge Equijoin (#18772)

## Which issue does this PR close?

- Closes #18804.

## Rationale for this change

## What changes are included in this PR?

Take correct columns

## Are these changes tested?

Yes, 

- added rust tests to hit invalid code paths
- sqltests
- fuzz tests enhancement to fuzzify columns count

Fuzz tests are taken from @rluvaton 's #18788 , excluding those this PR
doesn't fix:

```
    fuzz_cases::join_fuzz::test_right_anti_join_1k_binary_filtered
    fuzz_cases::join_fuzz::test_right_anti_join_1k_filtered
    fuzz_cases::join_fuzz::test_right_semi_join_1k_filtered
```

## Are there any user-facing changes?

Author: tglanz