[SPARK-13870][SQL] Add scalastyle escaping correctly in CVSSuite.scala

## What changes were proposed in this pull request?

When initial creating `CVSSuite.scala` in SPARK-12833, there was a typo on `scalastyle:on`: `scalstyle:on`. So, it turns off ScalaStyle checking for the rest of the file mistakenly. So, it can not find a violation on the code of `SPARK-12668` added recently. This issue fixes the existing escaping correctly and adds a new escaping for `SPARK-12668` code like the following.

```scala
   test("test aliases sep and encoding for delimiter and charset") {
+    // scalastyle:off
     val cars = sqlContext
...
       .load(testFile(carsFile8859))
+    // scalastyle:on
```
This will prevent future potential problems, too.

## How was this patch tested?

Pass the Jenkins test.

Author: Dongjoon Hyun <[email protected]>

Closes apache#11700 from dongjoon-hyun/SPARK-13870.

sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/csv/CSVSuite.scala

@@ -160,19 +160,21 @@ class CSVSuite extends QueryTest with SharedSQLContext with SQLTestUtils {
          |OPTIONS (path "${testFile(carsFile8859)}", header "true",
          |charset "iso-8859-1", delimiter "þ")
       """.stripMargin.replaceAll("\n", " "))
-    //scalstyle:on
+    // scalastyle:on
 
     verifyCars(sqlContext.table("carsTable"), withHeader = true)
   }
 
   test("test aliases sep and encoding for delimiter and charset") {
+    // scalastyle:off
     val cars = sqlContext
       .read
       .format("csv")
       .option("header", "true")
       .option("encoding", "iso-8859-1")
       .option("sep", "þ")
       .load(testFile(carsFile8859))
+    // scalastyle:on
 
     verifyCars(cars, withHeader = true)
   }