Fix data race in gtest_rate_limiter.cpp

[JinheLin]

What problem does this PR solve?

Issue Number: close #4420

Problem Summary:

std::default_random_engine is not thread-safe.

What is changed and how it works?

Make each thread has a private std::default_random_engine object.

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

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• JaySon-Huang
• lidezhu

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.

[JinheLin]

/run-all-tests

[lidezhu]

LGTM

[JaySon-Huang]

lgtm

[JinheLin]

/merge

[ti-chi-bot]

@JinheLin: 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: e1d1de4

[sre-bot]

Coverage for changed files

Filename                                                                                                        Regions    Missed Regions     Cover   Functions  Missed Functions  Executed       Lines      Missed Lines     Cover    Branches   Missed Branches     Cover
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
/home/jenkins/agent/workspace/tiflash-build-common/tiflash/dbms/src/Encryption/tests/gtest_rate_limiter.cpp        3137              1015    67.64%          39                 0   100.00%         698                20    97.13%         812               416    48.77%
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL                                                                                                              3137              1015    67.64%          39                 0   100.00%         698                20    97.13%         812               416    48.77%

Coverage summary

Functions  MissedFunctions  Executed  Lines   MissedLines  Cover
17044      9571             43.85%    191829  97043        49.41%

full coverage report (for internal network access only)