BR: fix backup ranges total time summary log (#35552)

[ti-srebot]

cherry-pick #35552 to release-6.1
You can switch your code base to this Pull Request by using git-extras:

# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/35702

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git push git@github.com:ti-srebot/tidb.git pr/35702:release-6.1-3c83cd310603

---

What problem does this PR solve?

Issue Number: close #35553

Problem Summary: Incorrect total time summary log of backup ranges process

[2022/06/16 00:03:22.387 -04:00] [INFO] [client.go:567] ["Backup Ranges"] [take=67ns]

What is changed and how it works?

Fix the code of printing the log. After fixed, it shows the correct time for backup ranges.

[2022/06/16 00:17:02.284 -04:00] [INFO] [client.go:538] ["Backup Ranges"] [take=595.572234ms]

Check List

Tests

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

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[ti-chi-bot]

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[ti-srebot]

/run-all-tests

[ti-srebot]

@joccau you're already a collaborator in bot's repo.

[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/3360e61cb72c69e6a701059f9800bccf398829e4

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: 3pointer, Leavrth

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-06-26 05:41:15.276109464 +0000 UTC m=+599840.677359896: ☑️ agreed by 3pointer.
• 2023-06-26 05:41:53.44928622 +0000 UTC m=+599878.850536670: ☑️ agreed by Leavrth.