[ISSUE #8127]Optimize the metric calculation logic of the time wheel

[3424672656]

Which Issue(s) This PR Fixes

Fixes #8127

Brief Description

How Did You Test This Change?

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 50.00000% with 6 lines in your changes missing coverage. Please review.

Project coverage is 47.88%. Comparing base (91fdc35) to head (73757e4).

Files with missing lines	Patch %	Lines
...apache/rocketmq/store/timer/TimerMessageStore.java	50.00%	5 Missing and 1 partial :warning:

Additional details and impacted files

@@              Coverage Diff              @@
##             develop    #8128      +/-   ##
=============================================
- Coverage      47.93%   47.88%   -0.06%     
+ Complexity     11887    11871      -16     
=============================================
  Files           1312     1312              
  Lines          91743    91753      +10     
  Branches       11753    11756       +3     
=============================================
- Hits           43980    43932      -48     
- Misses         42352    42394      +42     
- Partials        5411     5427      +16     

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[3424672656]

@RongtongJin PTAL~