[SPARK-16936][SQL] Case Sensitivity Support for Refresh Temp Table

### What changes were proposed in this pull request?
Currently, the `refreshTable` API is always case sensitive.

When users use the view name without the exact case match, the API silently ignores the call. Users might expect the command has been successfully completed. However, when users run the subsequent SQL commands, they might still get the exception, like
```
Job aborted due to stage failure:
Task 1 in stage 4.0 failed 1 times, most recent failure: Lost task 1.0 in stage 4.0 (TID 7, localhost):
java.io.FileNotFoundException:
File file:/private/var/folders/4b/sgmfldk15js406vk7lw5llzw0000gn/T/spark-bd4b9ea6-9aec-49c5-8f05-01cff426211e/part-r-00000-0c84b915-c032-4f2e-abf5-1d48fdbddf38.snappy.parquet does not exist
```

This PR is to fix the issue.

### How was this patch tested?
Added a test case.

Author: gatorsmile <gatorsmile@gmail.com>

Closes #14523 from gatorsmile/refreshTempTable.

(cherry picked from commit 5959df2)
Signed-off-by: Wenchen Fan <wenchen@databricks.com>

Author: gatorsmile

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/catalog/SessionCatalog.scala

@@ -495,7 +495,7 @@ class SessionCatalog(
     // If the database is defined, this is definitely not a temp table.
     // If the database is not defined, there is a good chance this is a temp table.
     if (name.database.isEmpty) {
-      tempTables.get(name.table).foreach(_.refresh())
+      tempTables.get(formatTableName(name.table)).foreach(_.refresh())
     }
   }
 
@@ -512,7 +512,7 @@ class SessionCatalog(
    * For testing only.
    */
   private[catalog] def getTempTable(name: String): Option[LogicalPlan] = synchronized {
-    tempTables.get(name)
+    tempTables.get(formatTableName(name))
   }
 
   // ----------------------------------------------------------------------------

sql/core/src/main/scala/org/apache/spark/sql/execution/SparkSqlParser.scala

@@ -1209,7 +1209,7 @@ class SparkSqlAstBuilder(conf: SQLConf) extends AstBuilder {
    *
    * For example:
    * {{{
-   *   CREATE [TEMPORARY] VIEW [IF NOT EXISTS] [db_name.]view_name
+   *   CREATE [OR REPLACE] [TEMPORARY] VIEW [IF NOT EXISTS] [db_name.]view_name
    *   [(column_name [COMMENT column_comment], ...) ]
    *   [COMMENT view_comment]
    *   [TBLPROPERTIES (property_name = property_value, ...)]

sql/core/src/test/scala/org/apache/spark/sql/MetadataCacheSuite.scala

@@ -20,6 +20,7 @@ package org.apache.spark.sql
 import java.io.File
 
 import org.apache.spark.SparkException
+import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.test.SharedSQLContext
 
 /**
@@ -85,4 +86,28 @@ class MetadataCacheSuite extends QueryTest with SharedSQLContext {
       assert(newCount > 0 && newCount < 100)
     }}
   }
+
+  test("case sensitivity support in temporary view refresh") {
+    withSQLConf(SQLConf.CASE_SENSITIVE.key -> "false") {
+      withTempView("view_refresh") {
+        withTempPath { (location: File) =>
+          // Create a Parquet directory
+          spark.range(start = 0, end = 100, step = 1, numPartitions = 3)
+            .write.parquet(location.getAbsolutePath)
+
+          // Read the directory in
+          spark.read.parquet(location.getAbsolutePath).createOrReplaceTempView("view_refresh")
+
+          // Delete a file
+          deleteOneFileInDirectory(location)
+          intercept[SparkException](sql("select count(*) from view_refresh").first())
+
+          // Refresh and we should be able to read it again.
+          spark.catalog.refreshTable("vIeW_reFrEsH")
+          val newCount = sql("select count(*) from view_refresh").first().getLong(0)
+          assert(newCount > 0 && newCount < 100)
+        }
+      }
+    }
+  }
 }