## What changes were proposed in this pull request?

This removes the remaining deprecated Octal escape literals. The followings are the warnings on those two lines.
```
LiteralExpressionSuite.scala:99: Octal escape literals are deprecated, use \u0000 instead.
HiveQlSuite.scala:74: Octal escape literals are deprecated, use \u002c instead.
```

## How was this patch tested?

Manual.
During building, there should be no warning on `Octal escape literals`.
```
mvn -DskipTests clean install
```

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11584 from dongjoon-hyun/SPARK-13400.