refactor: Fix a bunch of tests for new-streaming

[orlp]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 79.91%. Comparing base (1ee6a82) to head (85964d2).
Report is 43 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-stream/src/nodes/reduce.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18659      +/-   ##
==========================================
- Coverage   79.91%   79.91%   -0.01%     
==========================================
  Files        1506     1511       +5     
  Lines      203204   203201       -3     
  Branches     2891     2891              
==========================================
- Hits       162391   162382       -9     
- Misses      40263    40269       +6     
  Partials      550      550              

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