Revert "statistics: fix empty region count when resuming (#7009)"

[CabinfeverB]

This reverts commit 74ead5c.

What problem does this PR solve?

Issue Number: Close #7148

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.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• lhy1024
• rleungx

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

[rleungx]

CI failed

[codecov]

Codecov Report

Merging #7149 (d871637) into master (eb6953f) will increase coverage by 0.14%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #7149      +/-   ##
==========================================
+ Coverage   74.26%   74.40%   +0.14%     
==========================================
  Files         441      441              
  Lines       47216    47217       +1     
==========================================
+ Hits        35064    35131      +67     
+ Misses       9063     8997      -66     
  Partials     3089     3089              

Flag	Coverage Δ
unittests	74.40% <100.00%> (+0.14%)	⬆️

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

[CabinfeverB]

/merge

[ti-chi-bot]

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

/run-all-tests

You only need to trigger /merge once, and if the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

If you have any questions about the PR merge process, please refer to pr process.

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: d871637

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #7151.

[nolouch]

why does it affect the scatter?

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #7835.