fix(fuzz-tests): avoid to drop in-use database

[WenyXu]

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Refer to a related PR or issue link (optional)

What's changed and what's your intention?

Avoid to drop in-use database

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR requires documentation updates.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.13%. Comparing base (af486ec) to head (b9671de).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4049      +/-   ##
==========================================
- Coverage   85.45%   85.13%   -0.32%     
==========================================
  Files         983      984       +1     
  Lines      170505   170481      -24     
==========================================
- Hits       145702   145138     -564     
- Misses      24803    25343     +540     

[fengjiachun]

LGTM