[MINOR] [SQL] Fixes variable name typo

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Author: Cheng Lian <lian@databricks.com>

Closes #6038 from liancheng/fix-typo and squashes the following commits:

572c2a4 [Cheng Lian] Fixes variable name typo

sql/core/src/test/scala/org/apache/spark/sql/sources/CreateTableAsSelectSuite.scala

@@ -26,7 +26,7 @@ import org.apache.spark.util.Utils
 
 class CreateTableAsSelectSuite extends DataSourceTest with BeforeAndAfterAll {
 
-  import caseInsensisitiveContext._
+  import caseInsensitiveContext._
 
   var path: File = null
 

sql/core/src/test/scala/org/apache/spark/sql/sources/DDLTestSuite.scala

@@ -64,7 +64,7 @@ case class SimpleDDLScan(from: Int, to: Int, table: String)(@transient val sqlCo
 }
 
 class DDLTestSuite extends DataSourceTest {
-  import caseInsensisitiveContext._
+  import caseInsensitiveContext._
 
   before {
       sql(

sql/core/src/test/scala/org/apache/spark/sql/sources/DataSourceTest.scala

@@ -24,7 +24,7 @@ import org.scalatest.BeforeAndAfter
 
 abstract class DataSourceTest extends QueryTest with BeforeAndAfter {
   // We want to test some edge cases.
-  implicit val caseInsensisitiveContext = new SQLContext(TestSQLContext.sparkContext)
+  implicit val caseInsensitiveContext = new SQLContext(TestSQLContext.sparkContext)
 
-  caseInsensisitiveContext.setConf(SQLConf.CASE_SENSITIVE, "false")
+  caseInsensitiveContext.setConf(SQLConf.CASE_SENSITIVE, "false")
 }

sql/core/src/test/scala/org/apache/spark/sql/sources/FilteredScanSuite.scala

@@ -97,7 +97,7 @@ object FiltersPushed {
 
 class FilteredScanSuite extends DataSourceTest {
 
-  import caseInsensisitiveContext._
+  import caseInsensitiveContext._
 
   before {
     sql(

sql/core/src/test/scala/org/apache/spark/sql/sources/InsertSuite.scala

@@ -26,7 +26,7 @@ import org.apache.spark.util.Utils
 
 class InsertSuite extends DataSourceTest with BeforeAndAfterAll {
 
-  import caseInsensisitiveContext._
+  import caseInsensitiveContext._
 
   var path: File = null
 

sql/core/src/test/scala/org/apache/spark/sql/sources/PrunedScanSuite.scala

@@ -52,7 +52,7 @@ case class SimplePrunedScan(from: Int, to: Int)(@transient val sqlContext: SQLCo
 }
 
 class PrunedScanSuite extends DataSourceTest {
-  import caseInsensisitiveContext._
+  import caseInsensitiveContext._
 
   before {
     sql(

sql/core/src/test/scala/org/apache/spark/sql/sources/SaveLoadSuite.scala

@@ -27,7 +27,7 @@ import org.apache.spark.util.Utils
 
 class SaveLoadSuite extends DataSourceTest with BeforeAndAfterAll {
 
-  import caseInsensisitiveContext._
+  import caseInsensitiveContext._
 
   var originalDefaultSource: String = null
 

sql/core/src/test/scala/org/apache/spark/sql/sources/TableScanSuite.scala

@@ -88,7 +88,7 @@ case class AllDataTypesScan(
 }
 
 class TableScanSuite extends DataSourceTest {
-  import caseInsensisitiveContext._
+  import caseInsensitiveContext._
 
   var tableWithSchemaExpected = (1 to 10).map { i =>
     Row(