tests: Add code coverage scripts

[JaySon-Huang]

What problem does this PR solve?

Issue Number: ref #8889

Problem Summary:

What is changed and how it works?

Add a script for generating code coverage script.
The code coverage report could help find out the not-covered branches for refactoring. For example, prevent the bug of #8904 which was introduced during refactoring and non covered code path

To build coverage report, run the script under release-centos7-llvm

cd release-centos7-llvm
./gen_coverage.sh
# Or run with filter:
# FILTER='*DMFile*:*DeltaMerge*:*Segment*' ./gen_coverage.sh

# After the script finished, it will output the directory of code coverage report, you can check out the files by webbrowser
python3 -m http --directory "${REPORT_DIR}" "${REPORT_HTTP_PORT}"

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

None

[windtalker]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Lloyd-Pottiger, windtalker

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-04-09 12:54:14.588279896 +0000 UTC m=+966916.115820441: ☑️ agreed by Lloyd-Pottiger.
• 2024-04-10 00:59:05.653548446 +0000 UTC m=+1010407.181088991: ☑️ agreed by windtalker.

[ti-chi-bot]

@JaySon-Huang: Your PR was out of date, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

/run-all-tests

trigger some heavy tests which will not run always when PR updated.

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.

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[Lloyd-Pottiger]

/run-integration-test