[SPARK-3986][SQL] Fix package names to fit their directory names.

Package names of 2 test suites are different from their directory names.
- `GeneratedEvaluationSuite`
- `GeneratedMutableEvaluationSuite`

Author: Takuya UESHIN <ueshin@happy-camper.st>

Closes #2835 from ueshin/issues/SPARK-3986 and squashes the following commits:

fa2cc05 [Takuya UESHIN] Fix package names to fit their directory names.

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/GeneratedEvaluationSuite.scala

@@ -15,9 +15,8 @@
  * limitations under the License.
  */
 
-package org.apache.spark.sql.catalyst.optimizer
+package org.apache.spark.sql.catalyst.expressions
 
-import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.dsl.expressions._
 import org.apache.spark.sql.catalyst.expressions.codegen._
 

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/GeneratedMutableEvaluationSuite.scala

@@ -15,9 +15,8 @@
  * limitations under the License.
  */
 
-package org.apache.spark.sql.catalyst.optimizer
+package org.apache.spark.sql.catalyst.expressions
 
-import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.dsl.expressions._
 import org.apache.spark.sql.catalyst.expressions.codegen._