Optimize some e2e cases

[KanShiori]

What problem does this PR solve?

What is changed and how does it work?

Code changes

• [ ] Has Go code change
• [ ] Has CI related scripts change

Tests

• [ ] Unit test
• [ ] E2E test
• [ ] Manual test
• [ ] No code

Side effects

• [ ] Breaking backward compatibility
• [ ] Other side effects:

Related changes

• [ ] Need to cherry-pick to the release branch
• [ ] Need to update the documentation

Release Notes

Please refer to Release Notes Language Style Guide before writing the release note.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• DanielZhangQD

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[codecov-commenter]

Codecov Report

Merging #4674 (14b8d75) into master (20739ec) will increase coverage by 9.55%. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4674      +/-   ##
==========================================
+ Coverage   63.56%   73.12%   +9.55%     
==========================================
  Files         196      200       +4     
  Lines       21284    23817    +2533     
==========================================
+ Hits        13530    17415    +3885     
+ Misses       6534     5213    -1321     
+ Partials     1220     1189      -31     

Flag	Coverage Δ
e2e	60.14% <ø> (?)
unittest	63.59% <ø> (+0.02%)	:arrow_up:

[KanShiori]

/test pull-e2e-kind-br pull-e2e-kind-serial

[KanShiori]

/test pull-e2e-kind-tikv-scale-simultaneously