(pick-2.0-26031)[Fix](MySqlLoad) Fix meaningless thread creation every time checkpoint mysql load (#26031)

[CalvinKirs]

…

Add a unified thread name setting method

(cherry picked from commit eb2cbae)

Proposed changes

Issue Number: close #xxx

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...

[xiaokang]

run buildall

[doris-robot]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 48.03 seconds
stream load tsv: 554 seconds loaded 74807831229 Bytes, about 128 MB/s
stream load json: 21 seconds loaded 2358488459 Bytes, about 107 MB/s
stream load orc: 64 seconds loaded 1101869774 Bytes, about 16 MB/s
stream load parquet: 32 seconds loaded 861443392 Bytes, about 25 MB/s
insert into select: 29.3 seconds inserted 10000000 Rows, about 341K ops/s
storage size: 17162250461 Bytes

[CalvinKirs]

run buildall

[doris-robot]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 47.55 seconds
stream load tsv: 554 seconds loaded 74807831229 Bytes, about 128 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: 29.5 seconds inserted 10000000 Rows, about 338K ops/s
storage size: 17163888218 Bytes

[xiaokang]

#26031