Check date type to avoid scan all partitions

[xinghuayu007]

Describe the bug
select day from test where day='2020-10-32', table 'test' is parititioned by day. In this case, '2020-10-32' will be taken as CastExpr not LiteralExpr, and condition "day='2020-10-32'" will not be recognized as partitionfilter. This case will scan all partitions. To avoid scall all partitions, it is better to filter invalid date value.

Doris supports datetime with micro second, but save datetime with second in BE. Doris FE use joda time library to parse a datetime of string type. If a datetime with micro second, it will transfer it into CastExpr, which will be recognized into invalid time. Therefore in the begining, a datetime with micro second will be parsed into datetime with second. It make no difference. For expample k1 <= "2020-10-10 10:10:10.00" will be transfered into k1 <= "2020-10-10 10:10:10";

To Reproduce
Steps to reproduce the behavior:

1. create table:
   CREATE TABLE test (
   date datetime NULL COMMENT "日期",
   day date NULL COMMENT "",
   app_id varchar(1000) NULL COMMENT "",
   device_id int(11) 0 comment ""
   ) ENGINE=OLAP
   DUPLICATE KEY(date, day, app_id)
   COMMENT "OLAP"
   PARTITION BY RANGE(day)()
   DISTRIBUTED BY HASH(device_id) BUCKETS 64
   PROPERTIES (
   "replication_num" = "1",
   "dynamic_partition.enable" = "true",
   "dynamic_partition.time_unit" = "DAY",
   "dynamic_partition.time_zone" = "Asia/Shanghai",
   "dynamic_partition.start" = "-30",
   "dynamic_partition.end" = "3",
   "dynamic_partition.prefix" = "p",
   "dynamic_partition.replication_num" = "1",
   "dynamic_partition.buckets" = "32",
   "in_memory" = "false",
   "storage_format" = "V2"
   );
2. insert some data into each partition
3. execute a query which day is invalid, it will scan all partitions
   explain select day from test where '2020-10-32' = day;
   
   explain select day from test where 'hello' = day;
   
4. if day is valid, it will scan some partitions
   

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• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
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• Version [e.g. 22]

Additional context
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