Fix license and format coding style (part0)

[JaySon-Huang]

Split from #7962 because changing too many files in one PR will make the CI timeout

What problem does this PR solve?

Issue Number: ref #7968

Problem Summary:

The license header should be "PingCAP, Inc" instead of "PingCAP, Ltd", ref #7960

What is changed and how it works?

Fix the license by using the script in https://github.com/JaySon-Huang/licenseheaders/tree/my_fork, then format the code by .clang-format

gh repo clone JaySon-Huang/licenseheaders
./fix_license.sh /path/to/tiflash
cd /path/to/tiflash
python3 format-diff.py --diff_from `git merge-base upstream/master  HEAD`

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

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[JaySon-Huang]

close as we will temporary skip the clang-tidy check in #7962