[SPARK-14362][SPARK-14406][SQL][FOLLOW-UP] DDL Native Support: Drop View and Drop Table

#### What changes were proposed in this pull request?
In this PR, we are trying to address the comment in the original PR: https://github.com/apache/spark/commit/dfce9665c4b2b29a19e6302216dae2800da68ff9#commitcomment-17057030

In this PR, we checks if table/view exists at the beginning and then does not need to capture the exceptions, including `NoSuchTableException` and `InvalidTableException`. We still capture the NonFatal exception when doing `sqlContext.cacheManager.tryUncacheQuery`.

#### How was this patch tested?
The existing test cases should cover the code changes of this PR.

Author: gatorsmile <gatorsmile@gmail.com>

Closes #12321 from gatorsmile/dropViewFollowup.