[SPARK-39447][SQL] Avoid AssertionError in AdaptiveSparkPlanExec.doExecuteBroadcast

### What changes were proposed in this pull request?

Change `currentPhysicalPlan` to `inputPlan ` when we restore the broadcast exchange for DPP.

### Why are the changes needed?

The currentPhysicalPlan can be wrapped with broadcast query stage so it is not safe to match it. For example:
 The broadcast exchange which is added by DPP is running before than the normal broadcast exchange(e.g. introduced by join).

### Does this PR introduce _any_ user-facing change?

yes bug fix

### How was this patch tested?

add test

Closes #36974 from ulysses-you/inputplan.

Authored-by: ulysses-you <ulyssesyou18@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
(cherry picked from commit c320a5d)
Signed-off-by: Wenchen Fan <wenchen@databricks.com>

Author: ulysses-you

sql/core/src/main/scala/org/apache/spark/sql/execution/adaptive/AdaptiveSparkPlanExec.scala

@@ -659,7 +659,7 @@ case class AdaptiveSparkPlanExec(
       // node to prevent the loss of the `BroadcastExchangeExec` node in DPP subquery.
       // Here, we also need to avoid to insert the `BroadcastExchangeExec` node when the newPlan is
       // already the `BroadcastExchangeExec` plan after apply the `LogicalQueryStageStrategy` rule.
-      val finalPlan = currentPhysicalPlan match {
+      val finalPlan = inputPlan match {
         case b: BroadcastExchangeLike
           if (!newPlan.isInstanceOf[BroadcastExchangeLike]) => b.withNewChildren(Seq(newPlan))
         case _ => newPlan

sql/core/src/test/scala/org/apache/spark/sql/DynamicPartitionPruningSuite.scala

@@ -1694,6 +1694,25 @@ class DynamicPartitionPruningV1SuiteAEOff extends DynamicPartitionPruningV1Suite
 class DynamicPartitionPruningV1SuiteAEOn extends DynamicPartitionPruningV1Suite
   with EnableAdaptiveExecutionSuite {
 
+  test("SPARK-39447: Avoid AssertionError in AdaptiveSparkPlanExec.doExecuteBroadcast") {
+    val df = sql(
+      """
+        |WITH empty_result AS (
+        |  SELECT * FROM fact_stats WHERE product_id < 0
+        |)
+        |SELECT *
+        |FROM   (SELECT /*+ SHUFFLE_MERGE(fact_sk) */ empty_result.store_id
+        |        FROM   fact_sk
+        |               JOIN empty_result
+        |                 ON fact_sk.product_id = empty_result.product_id) t2
+        |       JOIN empty_result
+        |         ON t2.store_id = empty_result.store_id
+      """.stripMargin)
+
+    checkPartitionPruningPredicate(df, false, false)
+    checkAnswer(df, Nil)
+  }
+
   test("SPARK-37995: PlanAdaptiveDynamicPruningFilters should use prepareExecutedPlan " +
     "rather than createSparkPlan to re-plan subquery") {
     withSQLConf(SQLConf.DYNAMIC_PARTITION_PRUNING_ENABLED.key -> "true",