security: Do not let grpc reload ssh cert if not changed (#9068)

[ti-chi-bot]

This is an automated cherry-pick of #9068

What problem does this PR solve?

Issue Number: ref #8535

Problem Summary:

What is changed and how it works?

This pr does not fix #8535, but it will make sure if ssh cert is not changed, #8535 will not be triggered.

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

Reduced the probability of TiFlash crash due to ssh reload(#8535)

[windtalker]

LGTM

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-05-22 08:05:57.465416769 +0000 UTC m=+2245311.222552336: ☑️ agreed by zanmato1984.
• 2024-05-22 08:09:19.822475281 +0000 UTC m=+2245513.579610854: ☑️ agreed by windtalker.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gengliqi, windtalker, zanmato1984

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• OWNERS [gengliqi,windtalker,zanmato1984]

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[windtalker]

/run-all-tests

[windtalker]

/run-unit-tests

[windtalker]

/run-unit-tests

[JaySon-Huang]

Have we pick the related fix to release-7.5? @CalvinNeo

https://ci.pingcap.net/blue/organizations/jenkins/tiflash-ghpr-unit-tests/detail/tiflash-ghpr-unit-tests/13181/pipeline

[2024-05-22T09:28:58.998Z] �[0;33mNote: Google Test filter = ReadIndexTest.workers
[2024-05-22T09:28:58.998Z] �[m�[0;32m[==========] �[mRunning 1 test from 1 test case.
[2024-05-22T09:28:58.998Z] �[0;32m[----------] �[mGlobal test environment set-up.
[2024-05-22T09:28:58.998Z] �[0;32m[----------] �[m1 test from ReadIndexTest
[2024-05-22T09:28:58.998Z] �[0;32m[ RUN      ] �[mReadIndexTest.workers
[2024-05-22T09:28:58.998Z] [2024/05/22 17:28:49.144 +08:00] [WARN] [ProxyFFI.cpp:890] ["Set mock rust ptr gc function"] [source=MockSetRustGcHelper] [thread_id=1]
[2024-05-22T09:28:58.998Z] [2024/05/22 17:28:49.146 +08:00] [INFO] [ReadIndexWorker.cpp:997] ["Start read-index runner 2"] [source=ReadIndexWorkers] [thread_id=194]
[2024-05-22T09:28:58.998Z] [2024/05/22 17:28:49.148 +08:00] [INFO] [ReadIndexWorker.cpp:997] ["Start read-index runner 1"] [source=ReadIndexWorkers] [thread_id=195]
[2024-05-22T09:28:58.998Z] [2024/05/22 17:28:49.150 +08:00] [INFO] [ReadIndexWorker.cpp:997] ["Start read-index runner 0"] [source=ReadIndexWorkers] [thread_id=196]
[2024-05-22T09:28:58.998Z] /home/jenkins/agent/workspace/tiflash-build-common/tiflash/dbms/src/Storages/KVStore/tests/gtest_read_index_worker.cpp:376: Failure
[2024-05-22T09:28:58.998Z] Expected equality of these values:
[2024-05-22T09:28:58.998Z]   resps[2].first.read_index()
[2024-05-22T09:28:58.998Z]     Which is: 0
[2024-05-22T09:28:58.998Z]   669
[2024-05-22T09:28:58.998Z] libc++abi: terminating
[2024-05-22T09:28:58.998Z] Received signal Aborted