optimize: split the task thread pool for committing and rollbacking statuses

[liuqiufeng]

• I have registered the PR changes.

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

fixes #6478

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[funky-eyes]

LGTM

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 34.56790% with 53 lines in your changes are missing coverage. Please review.

Project coverage is 50.05%. Comparing base (e72babb) to head (2e79ecc).
Report is 8 commits behind head on 2.x.

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x    #6499      +/-   ##
============================================
- Coverage     50.19%   50.05%   -0.15%     
+ Complexity     5232     5211      -21     
============================================
  Files           942      944       +2     
  Lines         33221    33330     +109     
  Branches       4022     4029       +7     
============================================
+ Hits          16676    16684       +8     
- Misses        14938    15038     +100     
- Partials       1607     1608       +1     

Files	Coverage Δ
...c/main/java/org/apache/seata/common/Constants.java	100.00% <ø> (ø)
...org/apache/seata/server/session/GlobalSession.java	68.63% <0.00%> (-3.59%)	⬇️
...e/seata/server/coordinator/DefaultCoordinator.java	39.43% <35.00%> (-6.32%)	⬇️

... and 26 files with indirect coverage changes