[MINOR][SQL] Rename shouldBroadcast to isDynamicPruning in InSubqueryExec

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

Rename `shouldBroadcast` param to `isDynamicPruning`.

### Why are the changes needed?

Explicitly indicating the behavior mode of DPP

### Does this PR introduce _any_ user-facing change?
NO

### How was this patch tested?

Closes apache#42286 from liuzqt/insubqueryexec-rename.

Authored-by: Ziqi Liu <[email protected]>
Signed-off-by: Wenchen Fan <[email protected]>

Author: liuzqt

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

@@ -45,7 +45,7 @@ case class PlanAdaptiveSubqueries(
           )
         }
         val subquery = SubqueryExec(s"subquery#${exprId.id}", subqueryMap(exprId.id))
-        InSubqueryExec(expr, subquery, exprId, shouldBroadcast = true)
+        InSubqueryExec(expr, subquery, exprId, isDynamicPruning = false)
       case expressions.DynamicPruningSubquery(value, buildPlan,
           buildKeys, broadcastKeyIndex, onlyInBroadcast, exprId, _) =>
         val name = s"dynamicpruning#${exprId.id}"

sql/core/src/main/scala/org/apache/spark/sql/execution/subquery.scala

@@ -117,7 +117,7 @@ case class InSubqueryExec(
     child: Expression,
     plan: BaseSubqueryExec,
     exprId: ExprId,
-    shouldBroadcast: Boolean = false,
+    isDynamicPruning: Boolean = true,
     private var resultBroadcast: Broadcast[Array[Any]] = null,
     @transient private var result: Array[Any] = null)
   extends ExecSubqueryExpression with UnaryLike[Expression] with Predicate {
@@ -136,7 +136,7 @@ case class InSubqueryExec(
     } else {
       rows.map(_.get(0, child.dataType))
     }
-    if (shouldBroadcast) {
+    if (!isDynamicPruning) {
       resultBroadcast = plan.session.sparkContext.broadcast(result)
     }
   }
@@ -198,7 +198,7 @@ case class PlanSubqueries(sparkSession: SparkSession) extends Rule[SparkPlan] {
         }
         val executedPlan = QueryExecution.prepareExecutedPlan(sparkSession, query)
         InSubqueryExec(expr, SubqueryExec(s"subquery#${exprId.id}", executedPlan),
-          exprId, shouldBroadcast = true)
+          exprId, isDynamicPruning = false)
     }
   }
 }