Revert "[SPARK-8677] [SQL] Fix non-terminating decimal expansion for decimal divide operation"

This reverts commit 24fda73.

Author: yhuai

sql/catalyst/src/main/scala/org/apache/spark/sql/types/Decimal.scala

@@ -265,15 +265,8 @@ final class Decimal extends Ordered[Decimal] with Serializable {
 
   def * (that: Decimal): Decimal = Decimal(toBigDecimal * that.toBigDecimal)
 
-  def / (that: Decimal): Decimal = {
-    if (that.isZero) {
-      null
-    } else {
-      // To avoid non-terminating decimal expansion problem, we turn to Java BigDecimal's divide
-      // with specified ROUNDING_MODE.
-      Decimal(toJavaBigDecimal.divide(that.toJavaBigDecimal, ROUNDING_MODE.id))
-    }
-  }
+  def / (that: Decimal): Decimal =
+    if (that.isZero) null else Decimal(toBigDecimal / that.toBigDecimal)
 
   def % (that: Decimal): Decimal =
     if (that.isZero) null else Decimal(toBigDecimal % that.toBigDecimal)

sql/catalyst/src/test/scala/org/apache/spark/sql/types/decimal/DecimalSuite.scala

@@ -176,9 +176,4 @@ class DecimalSuite extends SparkFunSuite with PrivateMethodTester {
     val decimal = (Decimal(Long.MaxValue, 38, 0) * Decimal(Long.MaxValue, 38, 0)).toJavaBigDecimal
     assert(decimal.unscaledValue.toString === "85070591730234615847396907784232501249")
   }
-
-  test("fix non-terminating decimal expansion problem") {
-    val decimal = Decimal(1.0, 10, 3) / Decimal(3.0, 10, 3)
-    assert(decimal.toString === "0.333")
-  }
 }