Add test for zero partition range.

Author: viirya

sql/core/src/test/scala/org/apache/spark/sql/execution/PlannerSuite.scala

@@ -639,6 +639,12 @@ class PlannerSuite extends SharedSQLContext {
       case r: RangeExec => r
     }
     assert(rangeExecInOnePartition.head.outputPartitioning == SinglePartition)
+
+    val rangeInZeroPartition = spark.range(-10, -9, -20, 1)
+    val rangeExecInZeroPartition = rangeInZeroPartition.queryExecution.executedPlan.collect {
+      case r: RangeExec => r
+    }
+    assert(rangeExecInZeroPartition.head.outputPartitioning == UnknownPartitioning(0))
   }
 }