[SPARK-12057][SQL] Prevent failure on corrupt JSON records

This PR makes JSON parser and schema inference handle more cases where we have unparsed records. It is based on #10043. The last commit fixes the failed test and updates the logic of schema inference.

Regarding the schema inference change, if we have something like
```
{"f1":1}
[1,2,3]
```
originally, we will get a DF without any column.
After this change, we will get a DF with columns `f1` and `_corrupt_record`. Basically, for the second row, `[1,2,3]` will be the value of `_corrupt_record`.

When merge this PR, please make sure that the author is simplyianm.

JIRA: https://issues.apache.org/jira/browse/SPARK-12057

Closes #10043

Author: Ian Macalinao <me@ian.pw>
Author: Yin Huai <yhuai@databricks.com>

Closes #10288 from yhuai/handleCorruptJson.