[SPARK-32594][SQL] Fix serialization of dates inserted to Hive tables

### What changes were proposed in this pull request?
Fix `DaysWritable` by overriding parent's method `def get(doesTimeMatter: Boolean): Date` from `DateWritable` instead of `Date get()` because the former one uses the first one. The bug occurs because `HiveOutputWriter.write()` call `def get(doesTimeMatter: Boolean): Date` transitively with default implementation from the parent class  `DateWritable` which doesn't respect date rebases and uses not initialized `daysSinceEpoch` (0 which `1970-01-01`).

### Why are the changes needed?
The changes fix the bug:
```sql
spark-sql> CREATE TABLE table1 (d date);
spark-sql> INSERT INTO table1 VALUES (date '2020-08-11');
spark-sql> SELECT * FROM table1;
1970-01-01
```
The expected result of the last SQL statement must be **2020-08-11** but got **1970-01-01**.

### Does this PR introduce _any_ user-facing change?
Yes. After the fix, `INSERT` work correctly:
```sql
spark-sql> SELECT * FROM table1;
2020-08-11
```

### How was this patch tested?
Add new test to `HiveSerDeReadWriteSuite`

Closes #29409 from MaxGekk/insert-date-into-hive-table.

Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>

Author: MaxGekk

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DaysWritable.scala

@@ -54,7 +54,9 @@ class DaysWritable(
   }
 
   override def getDays: Int = julianDays
-  override def get(): Date = new Date(DateWritable.daysToMillis(julianDays))
+  override def get(doesTimeMatter: Boolean): Date = {
+    new Date(DateWritable.daysToMillis(julianDays, doesTimeMatter))
+  }
 
   override def set(d: Int): Unit = {
     gregorianDays = d

sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveSerDeReadWriteSuite.scala

@@ -184,4 +184,12 @@ class HiveSerDeReadWriteSuite extends QueryTest with SQLTestUtils with TestHiveS
       checkComplexTypes(fileFormat)
     }
   }
+
+  test("SPARK-32594: insert dates to a Hive table") {
+    withTable("table1") {
+      sql("CREATE TABLE table1 (d date)")
+      sql("INSERT INTO table1 VALUES (date '2020-08-11')")
+      checkAnswer(spark.table("table1"), Row(Date.valueOf("2020-08-11")))
+    }
+  }
 }