[SPARK-17750][SQL] Fix CREATE VIEW with INTERVAL arithmetic.

## What changes were proposed in this pull request?

Currently, Spark raises `RuntimeException` when creating a view with timestamp with INTERVAL arithmetic like the following. The root cause is the arithmetic expression, `TimeAdd`, was transformed into `timeadd` function as a VIEW definition. This PR fixes the SQL definition of `TimeAdd` and `TimeSub` expressions.

```scala
scala> sql("CREATE TABLE dates (ts TIMESTAMP)")

scala> sql("CREATE VIEW view1 AS SELECT ts + INTERVAL 1 DAY FROM dates")
java.lang.RuntimeException: Failed to analyze the canonicalized SQL: ...
```

## How was this patch tested?

Pass Jenkins with a new testcase.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #15318 from dongjoon-hyun/SPARK-17750.