[SPARK-3598][SQL]cast to timestamp should be the same as hive

[adrian-wang]

this patch fixes timestamp smaller than 0 and cast int as timestamp

select cast(1000 as timestamp) from src limit 1;

should return 1970-01-01 00:00:01, but we now take it as 1000 seconds.
also, current implementation has bug when the time is before 1970-01-01 00:00:00.
@rxin @marmbrus @chenghao-intel

[SparkQA]

QA tests have started for PR 2458 at commit 4274b1d.

• This patch merges cleanly.

[SparkQA]

QA tests have finished for PR 2458 at commit 4274b1d.

• This patch passes unit tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • sealed trait Matrix extends Serializable
  • class SparseMatrix(
  • sealed trait Vector extends Serializable

[marmbrus]

Thanks! Merged to master.