tikv_util: handle cgroup path building error (#12485)

[CalvinNeo]

close tikv#12479, ref tikv#12585

Handle cgroup path building error gracefully

Signed-off-by: tabokie xy.tao@outlook.com

Co-authored-by: Ti Chi Robot ti-community-prow-bot@tidb.io

What problem does this PR solve?

Issue Number: close #xxx

Problem Summary:

What is changed and how it works?

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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