Fix issues found in Storage Hammer

[Besroy]

1. concurrency issue between remove logdev and device truncate
2. log index→entry misalignment (issue: log index→entry misalignment #857)
3. fix metric compute logic

Related sisl pr: eBay/sisl#294

[codecov-commenter]

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Codecov Report

❌ Patch coverage is 25.00000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 48.33%. Comparing base (fe47d46) to head (f514f61).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/lib/logstore/log_store.cpp	0.00%	0 Missing and 1 partial ⚠️
src/lib/logstore/log_store_service.cpp	0.00%	0 Missing and 1 partial ⚠️
.../lib/replication/log_store/home_raft_log_store.cpp	50.00%	0 Missing and 1 partial ⚠️
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Additional details and impacted files

@@            Coverage Diff             @@
##           master     #858      +/-   ##
==========================================
+ Coverage   48.26%   48.33%   +0.06%     
==========================================
  Files         110      110              
  Lines       12872    12872              
  Branches     6176     6176              
==========================================
+ Hits         6213     6222       +9     
+ Misses       2567     2556      -11     
- Partials     4092     4094       +2     

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[xiaoxichen]

can you in the commit log providing more info for the first 2 fixes