[SPARK-11379][SQL] ExpressionEncoder can't handle top level primitive type correctly

[cloud-fan]

For inner primitive type(e.g. inside Product), we use schemaFor to get the catalyst type for it, https://github.com/apache/spark/blob/master/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala#L403.

However, for top level primitive type, we use dataTypeFor, which is wrong.

[cloud-fan]

cc @marmbrus

[cloud-fan]

retest this please.

[SparkQA]

Test build #44553 has finished for PR 9337 at commit 8b98d03.

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

[marmbrus]

Thanks, merging to master.