[CELEBORN-2243] During the close phase of hashWriter, pushData and mergeData are sent in parallel

[mcdull-zhang]

What changes were proposed in this pull request?

Optimize the close process of HashBasedShuffleWriter：

BeforePR：First, synchronously wait for pushData in the dataPusher queue to complete, then send mergeData and synchronously wait.
AfterPR：During the process of sending pushData by dataPusher, mergeData is also constructed and sent simultaneously.

Optimization results: The table below shows the shuffle write time for TPCH 1TB.

	SortBasedShuffleWriter	HashBasedShuffleWriter
Before	615.44W ms	502.31W ms
After	442.47W ms	434.77W ms

Note: This is the result of multiple optimizations combined;
other optimizations will be submitted as pull requests in the future.

Why are the changes needed?

Improve performance by increasing the parallelism of pushing/merging data.

Does this PR resolve a correctness bug?

NO

Does this PR introduce any user-facing change?

NO

How was this patch tested?

Exists Unit Test.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 67.30%. Comparing base (ffff5bb) to head (87eb227).
⚠️ Report is 16 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3574      +/-   ##
==========================================
+ Coverage   67.05%   67.30%   +0.25%     
==========================================
  Files         357      357              
  Lines       21779    21847      +68     
  Branches     1930     1938       +8     
==========================================
+ Hits        14602    14702     +100     
+ Misses       6160     6129      -31     
+ Partials     1017     1016       -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.