[SPARK-34001][SQL][TESTS] Remove unused runShowTablesSql() in DataSou…

…rceV2SQLSuite.scala

### What changes were proposed in this pull request?

After #30287, `runShowTablesSql()` in `DataSourceV2SQLSuite.scala` is no longer used. This PR removes the unused method.

### Why are the changes needed?

To remove unused method.

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

Existing test.

Closes #31022 from imback82/33382-followup.

Authored-by: Terry Kim <yuminkim@gmail.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>

sql/core/src/test/scala/org/apache/spark/sql/connector/DataSourceV2SQLSuite.scala

@@ -35,7 +35,7 @@ import org.apache.spark.sql.internal.{SQLConf, StaticSQLConf}
 import org.apache.spark.sql.internal.SQLConf.{PARTITION_OVERWRITE_MODE, PartitionOverwriteMode, V2_SESSION_CATALOG_IMPLEMENTATION}
 import org.apache.spark.sql.internal.connector.SimpleTableProvider
 import org.apache.spark.sql.sources.SimpleScanSource
-import org.apache.spark.sql.types.{BooleanType, LongType, StringType, StructField, StructType}
+import org.apache.spark.sql.types.{LongType, StringType, StructField, StructType}
 import org.apache.spark.sql.util.CaseInsensitiveStringMap
 import org.apache.spark.storage.StorageLevel
 import org.apache.spark.unsafe.types.UTF8String
@@ -991,26 +991,6 @@ class DataSourceV2SQLSuite
       " only SessionCatalog supports this command."))
   }
 
-  private def runShowTablesSql(
-      sqlText: String,
-      expected: Seq[Row],
-      expectV2Catalog: Boolean = true): Unit = {
-    val schema = if (expectV2Catalog) {
-      new StructType()
-        .add("namespace", StringType, nullable = false)
-        .add("tableName", StringType, nullable = false)
-    } else {
-      new StructType()
-        .add("database", StringType, nullable = false)
-        .add("tableName", StringType, nullable = false)
-        .add("isTemporary", BooleanType, nullable = false)
-    }
-
-    val df = spark.sql(sqlText)
-    assert(df.schema === schema)
-    assert(expected === df.collect())
-  }
-
   test("CreateNameSpace: basic tests") {
     // Session catalog is used.
     withNamespace("ns") {