Fix test14

[lhy1024]

What problem does this PR solve?

Issue Number: Close #xxx

What is changed and how does it work?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Code changes

• Has the configuration change
• Has HTTP API interfaces changed (Don't forget to add the declarative for the new API)
• Has persistent data change

Side effects

• Possible performance regression
• Increased code complexity
• Breaking backward compatibility

Related changes

• PR to update pingcap/docs/pingcap/docs-cn:
• PR to update pingcap/tiup:
• Need to cherry-pick to the release branch

Release note

None.

[codecov-commenter]

Codecov Report

Merging #25 (dbaeceb) into master (86831ce) will increase coverage by 0.00%.
The diff coverage is 66.66%.

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Additional details and impacted files

@@           Coverage Diff           @@
##           master      #25   +/-   ##
=======================================
  Coverage   74.29%   74.30%           
=======================================
  Files         451      451           
  Lines       48863    48872    +9     
=======================================
+ Hits        36305    36316   +11     
+ Misses       9349     9336   -13     
- Partials     3209     3220   +11     

Flag	Coverage Δ
unittests	74.30% <66.66%> (+<0.01%)	⬆️

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