schedule: fix datarace in operator.check

[lhy1024]

What problem does this PR solve?

Issue Number: Close #8263

What is changed and how does it work?

Check List

Tests

• Unit test
• Manual test (add detailed scripts or steps below)
  go test -timeout 120s -run ^TestOperatorCheckConcurrently$ github.com/tikv/pd/pkg/schedule/operator -race
• in master

==================
WARNING: DATA RACE
Read at 0x00c0004dc240 by goroutine 212:
  github.com/tikv/pd/pkg/schedule/operator.(*Operator).Check()
      /home/lhy1024/pd/pkg/schedule/operator/operator.go:382 +0x5c4
  github.com/tikv/pd/pkg/schedule/operator.TestOperatorCheckConcurrently.func1()
      /home/lhy1024/pd/pkg/schedule/operator/operator_test.go:593 +0xbe

Previous write at 0x00c0004dc240 by goroutine 215:
  sync/atomic.CompareAndSwapInt64()
      /usr/lib/go/src/runtime/race_amd64.s:316 +0xb
  sync/atomic.CompareAndSwapInt64()
      <autogenerated>:1 +0x1a
  github.com/tikv/pd/pkg/schedule/operator.TestOperatorCheckConcurrently.func1()
      /home/lhy1024/pd/pkg/schedule/operator/operator_test.go:593 +0xbe

Goroutine 212 (running) created at:
  github.com/tikv/pd/pkg/schedule/operator.TestOperatorCheckConcurrently()
      /home/lhy1024/pd/pkg/schedule/operator/operator_test.go:591 +0x487
  testing.tRunner()
      /usr/lib/go/src/testing/testing.go:1689 +0x21e
  testing.(*T).Run.gowrap1()
      /usr/lib/go/src/testing/testing.go:1742 +0x44

Goroutine 215 (running) created at:
  github.com/tikv/pd/pkg/schedule/operator.TestOperatorCheckConcurrently()
      /home/lhy1024/pd/pkg/schedule/operator/operator_test.go:591 +0x487
  testing.tRunner()
      /usr/lib/go/src/testing/testing.go:1689 +0x21e
  testing.(*T).Run.gowrap1()
      /usr/lib/go/src/testing/testing.go:1742 +0x44
==================
--- FAIL: TestOperatorCheckConcurrently (0.00s)
    testing.go:1398: race detected during execution of test
FAIL
FAIL    github.com/tikv/pd/pkg/schedule/operator        0.103s
FAIL

• with this pr

ok      github.com/tikv/pd/pkg/schedule/operator        1.098s

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• HuSharp
• rleungx

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[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 77.50%. Comparing base (f69d600) to head (1665065).
Report is 138 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8264      +/-   ##
==========================================
+ Coverage   77.32%   77.50%   +0.18%     
==========================================
  Files         471      471              
  Lines       61380    61381       +1     
==========================================
+ Hits        47463    47575     +112     
+ Misses      10365    10258     -107     
+ Partials     3552     3548       -4     

Flag	Coverage Δ
unittests	77.50% <75.00%> (+0.18%)	⬆️

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[rleungx]

Is stepsTime useless?

[lhy1024]

If the code goes into this branch, it means that o.stepsTime[step]) is now time.Now()

[ti-chi-bot]

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[HuSharp]

please add affect label

[lhy1024]

/merge

[ti-chi-bot]

@lhy1024: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

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[ti-chi-bot]

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

Commit hash: 849163a

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #8401.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.1: #8469.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #8578.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #8579.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #8580.