[SPARK-23400][SQL] Add a constructors for ScalaUDF

## What changes were proposed in this pull request?

In this upcoming 2.3 release, we changed the interface of `ScalaUDF`. Unfortunately, some Spark packages (e.g., spark-deep-learning) are using our internal class `ScalaUDF`. In the release 2.3, we added new parameters into this class. The users hit the binary compatibility issues and got the exception:

```
> java.lang.NoSuchMethodError: org.apache.spark.sql.catalyst.expressions.ScalaUDF.<init>(Ljava/lang/Object;Lorg/apache/spark/sql/types/DataType;Lscala/collection/Seq;Lscala/collection/Seq;Lscala/Option;)V
```

This PR is to improve the backward compatibility. However, we definitely should not encourage the external packages to use our internal classes. This might make us hard to maintain/develop the codes in Spark.

## How was this patch tested?
N/A

Author: gatorsmile <[email protected]>

Closes apache#20591 from gatorsmile/scalaUDF.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/ScalaUDF.scala

@@ -49,6 +49,17 @@ case class ScalaUDF(
     udfDeterministic: Boolean = true)
   extends Expression with ImplicitCastInputTypes with NonSQLExpression with UserDefinedExpression {
 
+  // The constructor for SPARK 2.1 and 2.2
+  def this(
+      function: AnyRef,
+      dataType: DataType,
+      children: Seq[Expression],
+      inputTypes: Seq[DataType],
+      udfName: Option[String]) = {
+    this(
+      function, dataType, children, inputTypes, udfName, nullable = true, udfDeterministic = true)
+  }
+
   override lazy val deterministic: Boolean = udfDeterministic && children.forall(_.deterministic)
 
   override def toString: String =