*: fix race in hot region config (#4167)

[ti-chi-bot]

This is an automated cherry-pick of #4167

What problem does this PR solve?

Close #4159.

What is changed and how it works?

Use the lock correctly.

Check List

Tests

• Unit test

Release note

Fix the data race problem of hot region config

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• HunDunDM
• nolouch

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[codecov]

Codecov Report

Merging #4170 (c7ab2be) into release-5.2 (bb4b5c7) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head c7ab2be differs from pull request most recent head 81e2c1c. Consider uploading reports for the commit 81e2c1c to get more accurate results

@@             Coverage Diff              @@
##           release-5.2    #4170   +/-   ##
============================================
  Coverage        74.68%   74.69%           
============================================
  Files              249      249           
  Lines            25537    25539    +2     
============================================
+ Hits             19073    19077    +4     
+ Misses            4778     4775    -3     
- Partials          1686     1687    +1     

Flag	Coverage Δ
unittests	74.69% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
server/schedulers/hot_region_config.go	92.09% <100.00%> (+0.09%)	⬆️
pkg/tempurl/tempurl.go	45.00% <0.00%> (-15.00%)	⬇️
server/schedule/operator/step.go	67.44% <0.00%> (-2.33%)	⬇️
server/tso/tso.go	62.98% <0.00%> (-2.21%)	⬇️
server/election/lease.go	94.91% <0.00%> (-1.70%)	⬇️
server/schedule/operator_controller.go	84.75% <0.00%> (-0.80%)	⬇️
server/grpc_service.go	47.00% <0.00%> (-0.46%)	⬇️
server/server.go	71.27% <0.00%> (-0.31%)	⬇️
client/client.go	71.82% <0.00%> (-0.14%)	⬇️
server/cluster/coordinator.go	73.58% <0.00%> (+0.67%)	⬆️
... and 4 more

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[nolouch]

/merge

[ti-chi-bot]

@nolouch: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: add2d38

[nolouch]

/merge

[ti-chi-bot]

@nolouch: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.