[Fix](planner)fix incorrect nullable in ctas.

[sohardforaname]

Proposed changes

Issue Number: close #xxx

ctas with outer join like

create table a (
        id int not null,
        name varchar(20) not null
)
distributed by hash(id) buckets 4
properties (
        "replication_num"="1"
);

create table b (
        id int not null,
        age int not null
)
distributed by hash(id) buckets 4
properties (
        "replication_num"="1"
);

insert into a values(1, 'ww'), (2, 'zs');
insert into b values(1, 22);

create table c properties("replication_num"="1") as select a.id, a.name, b.age from a left join b on a.id = b.id;

the column 'age' in c is not null, but nullable is expected, we fix it by use the nullable mode of the outputs of root plan fragment.

Further comments

If this is a relatively large or complex change, kick off the discussion at dev@doris.apache.org by explaining why you chose the solution you did and what alternatives you considered, etc...

[sohardforaname]

run buildall

[hello-stephen]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 48.28 seconds
stream load tsv: 507 seconds loaded 74807831229 Bytes, about 140 MB/s
stream load json: 20 seconds loaded 2358488459 Bytes, about 112 MB/s
stream load orc: 66 seconds loaded 1101869774 Bytes, about 15 MB/s
stream load parquet: 31 seconds loaded 861443392 Bytes, about 26 MB/s
insert into select: 29.4 seconds inserted 10000000 Rows, about 340K ops/s
storage size: 17162483244 Bytes

[sohardforaname]

run buildall

[hello-stephen]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 47.57 seconds
stream load tsv: 511 seconds loaded 74807831229 Bytes, about 139 MB/s
stream load json: 20 seconds loaded 2358488459 Bytes, about 112 MB/s
stream load orc: 65 seconds loaded 1101869774 Bytes, about 16 MB/s
stream load parquet: 31 seconds loaded 861443392 Bytes, about 26 MB/s
insert into select: 29.3 seconds inserted 10000000 Rows, about 341K ops/s
storage size: 17162540139 Bytes

[sohardforaname]

run buildall

[hello-stephen]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 45.42 seconds
stream load tsv: 510 seconds loaded 74807831229 Bytes, about 139 MB/s
stream load json: 20 seconds loaded 2358488459 Bytes, about 112 MB/s
stream load orc: 65 seconds loaded 1101869774 Bytes, about 16 MB/s
stream load parquet: 31 seconds loaded 861443392 Bytes, about 26 MB/s
insert into select: 29.1 seconds inserted 10000000 Rows, about 343K ops/s
storage size: 17162199590 Bytes

[sohardforaname]

run buildall

[hello-stephen]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 44.99 seconds
stream load tsv: 511 seconds loaded 74807831229 Bytes, about 139 MB/s
stream load json: 20 seconds loaded 2358488459 Bytes, about 112 MB/s
stream load orc: 65 seconds loaded 1101869774 Bytes, about 16 MB/s
stream load parquet: 31 seconds loaded 861443392 Bytes, about 26 MB/s
insert into select: 29.2 seconds inserted 10000000 Rows, about 342K ops/s
storage size: 17161891481 Bytes

[sohardforaname]

run buildall

[hello-stephen]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 45.56 seconds
stream load tsv: 510 seconds loaded 74807831229 Bytes, about 139 MB/s
stream load json: 20 seconds loaded 2358488459 Bytes, about 112 MB/s
stream load orc: 68 seconds loaded 1101869774 Bytes, about 15 MB/s
stream load parquet: 31 seconds loaded 861443392 Bytes, about 26 MB/s
insert into select: 29.4 seconds inserted 10000000 Rows, about 340K ops/s
storage size: 17162142474 Bytes

[sohardforaname]

run buildall

[hello-stephen]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 45.28 seconds
stream load tsv: 545 seconds loaded 74807831229 Bytes, about 130 MB/s
stream load json: 20 seconds loaded 2358488459 Bytes, about 112 MB/s
stream load orc: 65 seconds loaded 1101869774 Bytes, about 16 MB/s
stream load parquet: 31 seconds loaded 861443392 Bytes, about 26 MB/s
insert into select: 100.0 seconds inserted 10000000 Rows, about 100K ops/s
storage size: 17162138601 Bytes

[github-actions]

PR approved by at least one committer and no changes requested.

[github-actions]

PR approved by anyone and no changes requested.