removed unused import

Author: tejasapatil

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

@@ -21,7 +21,6 @@ import scala.language.existentials
 
 import org.apache.spark.sql.catalyst.analysis.UnresolvedRelation
 import org.apache.spark.sql.catalyst.TableIdentifier
-import org.apache.spark.sql.execution.SortExec
 import org.apache.spark.sql.execution.joins._
 import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.test.SharedSQLContext