[Correctness] test single condition (equal) for left anti join using ShuffledHashJoin FAILED

[xumingming]

The following test failed when auron is enabled:

https://github.com/apache/spark/blob/b45f071cd1b653731ae5b1c97c77d1f47560b177/sql/core/src/test/scala/org/apache/spark/sql/execution/joins/ExistenceJoinSuite.scala#L265-L271

2025-12-31T08:31:29.1564782Z - test single condition (equal) for left anti join using ShuffledHashJoin (whole-stage-codegen off) *** FAILED ***
2025-12-31T08:31:29.1565653Z   Results do not match for Spark plan:
2025-12-31T08:31:29.1566368Z    ShuffledHashJoin [a#15], [c#21], LeftAnti, BuildRight
2025-12-31T08:31:29.1567196Z   :- Exchange hashpartitioning(a#15, 1), ENSURE_REQUIREMENTS, [plan_id=3295]
2025-12-31T08:31:29.1567847Z   :  +- Scan ExistingRDD[a#15,b#16]
2025-12-31T08:31:29.1568591Z   +- Exchange hashpartitioning(c#21, 1), ENSURE_REQUIREMENTS, [plan_id=3296]
2025-12-31T08:31:29.1569346Z      +- Scan ExistingRDD[c#21,d#22]
2025-12-31T08:31:29.1569735Z   
2025-12-31T08:31:29.1570174Z    
2025-12-31T08:31:29.1570459Z    == Results ==
2025-12-31T08:31:29.1570871Z    !== Expected Answer - 4 ==   == Actual Answer - 2 ==
2025-12-31T08:31:29.1571378Z    [1,2.0]                     [1,2.0]
2025-12-31T08:31:29.1571793Z    [1,2.0]                     [1,2.0]
2025-12-31T08:31:29.1572207Z   ![null,5.0]                  
2025-12-31T08:31:29.1572627Z   ![null,null] (SparkPlanTest.scala:95)