[SQL][SPARK-16888] Implements eval method for expression AssertNotNull

[clockfly]

What changes were proposed in this pull request?

Implements eval() method for expression AssertNotNull so that we can convert local projection on LocalRelation to another LocalRelation.

Before change:

scala> import org.apache.spark.sql.catalyst.dsl.expressions._
scala> import org.apache.spark.sql.catalyst.expressions.objects.AssertNotNull
scala> import org.apache.spark.sql.Column
scala> case class A(a: Int)
scala> Seq((A(1),2)).toDS().select(new Column(AssertNotNull("_1".attr, Nil))).explain

java.lang.UnsupportedOperationException: Only code-generated evaluation is supported.
  at org.apache.spark.sql.catalyst.expressions.objects.AssertNotNull.eval(objects.scala:850)
  ...

After the change:

scala> Seq((A(1),2)).toDS().select(new Column(AssertNotNull("_1".attr, Nil))).explain(true)

== Parsed Logical Plan ==
'Project [assertnotnull('_1) AS assertnotnull(_1)#5]
+- LocalRelation [_1#2, _2#3]

== Analyzed Logical Plan ==
assertnotnull(_1): struct<a:int>
Project [assertnotnull(_1#2) AS assertnotnull(_1)#5]
+- LocalRelation [_1#2, _2#3]

== Optimized Logical Plan ==
LocalRelation [assertnotnull(_1)#5]

== Physical Plan ==
LocalTableScan [assertnotnull(_1)#5]

How was this patch tested?

Unit test.

[SparkQA]

Test build #63189 has finished for PR 14486 at commit 595c6c8.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[cloud-fan]

LGTM, can you create a JIRA for it?

[cloud-fan]

thanks, merging to master!