test: fix old version connect timeout

[Bughue]

• I have read the CONTRIBUTING.md guidelines.
• I have registered the PR changes.

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

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

fixes #7558

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.41%. Comparing base (3495837) to head (51fa071).
⚠️ Report is 2 commits behind head on 2.x.

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x    #7679      +/-   ##
============================================
+ Coverage     61.28%   61.41%   +0.12%     
  Complexity      666      666              
============================================
  Files          1314     1314              
  Lines         49817    49817              
  Branches       5858     5858              
============================================
+ Hits          30532    30593      +61     
+ Misses        16545    16479      -66     
- Partials       2740     2745       +5     

Files with missing lines	Coverage Δ
...che/seata/core/rpc/netty/NettyServerBootstrap.java	74.22% <100.00%> (ø)

... and 11 files with indirect coverage changes

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[slievrly]

LGTM