[SPARK-28015][SQL] Check stringToDate() consumes entire input for the yyyy and yyyy-[m]m formats

Fix `stringToDate()` for the formats `yyyy` and `yyyy-[m]m` that assumes there are no additional chars after the last components `yyyy` and `[m]m`. In the PR, I propose to check that entire input was consumed for the formats.

After the fix, the input `1999 08 01` will be invalid because it matches to the pattern `yyyy` but the strings contains additional chars ` 08 01`.

Since Spark 1.6.3 ~ 2.4.3, the behavior is the same.
```
spark-sql> SELECT CAST('1999 08 01' AS DATE);
1999-01-01
```

This PR makes it return NULL like Hive.
```
spark-sql> SELECT CAST('1999 08 01' AS DATE);
NULL
```

Added new checks to `DateTimeUtilsSuite` for the `1999 08 01` and `1999 08` inputs.

Closes #25097 from MaxGekk/spark-28015-invalid-date-format.

Authored-by: Maxim Gekk <maxim.gekk@databricks.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>

Author: MaxGekk

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala

@@ -498,6 +498,10 @@ object DateTimeUtils {
       // year should have exact four digits
       return None
     }
+    if (i < 2 && j < bytes.length) {
+      // For the `yyyy` and `yyyy-[m]m` formats, entire input must be consumed.
+      return None
+    }
     segments(i) = currentSegmentValue
     if (isInvalidDate(segments(0), segments(1), segments(2))) {
       return None

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/util/DateTimeUtilsSuite.scala

@@ -160,6 +160,9 @@ class DateTimeUtilsSuite extends SparkFunSuite {
     assert(stringToDate(UTF8String.fromString("015-03-18")).isEmpty)
     assert(stringToDate(UTF8String.fromString("015")).isEmpty)
     assert(stringToDate(UTF8String.fromString("02015")).isEmpty)
+    assert(stringToDate(UTF8String.fromString("1999 08 01")).isEmpty)
+    assert(stringToDate(UTF8String.fromString("1999-08 01")).isEmpty)
+    assert(stringToDate(UTF8String.fromString("1999 08")).isEmpty)
   }
 
   test("string to time") {
@@ -336,6 +339,9 @@ class DateTimeUtilsSuite extends SparkFunSuite {
       checkStringToTimestamp("2015-03-18T12:03.17-20:0", None)
       checkStringToTimestamp("2015-03-18T12:03.17-0:70", None)
       checkStringToTimestamp("2015-03-18T12:03.17-1:0:0", None)
+      checkStringToTimestamp("1999 08 01", None)
+      checkStringToTimestamp("1999-08 01", None)
+      checkStringToTimestamp("1999 08", None)
 
       // Truncating the fractional seconds
       c = Calendar.getInstance(TimeZone.getTimeZone("GMT+00:00"))