pprof: change debug 2 to debug 1 to avoid gc stw

[HuSharp]

What problem does this PR solve?

Issue Number: Close #7934

What is changed and how does it work?

can check more detail in pingcap/tidb#48695

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

Release note

None.

[ti-chi-bot]

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• lhy1024

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[HuSharp]

/check-issue-triage-complete

[codecov]

Codecov Report

Merging #7935 (951e179) into master (da3b6e3) will decrease coverage by 0.10%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7935      +/-   ##
==========================================
- Coverage   73.54%   73.44%   -0.10%     
==========================================
  Files         436      436              
  Lines       48349    48349              
==========================================
- Hits        35558    35512      -46     
- Misses       9731     9770      +39     
- Partials     3060     3067       +7     

Flag	Coverage Δ
unittests	73.44% <100.00%> (-0.10%)	⬇️

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[nolouch]

It's better to keep consist with tidb pingcap/tidb#9651.
I think it's ok because it is only called manually.

[HuSharp]

It's better to keep consist with tidb pingcap/tidb#9651. I think it's ok because it is only called manually.

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