fix case where queue wait time can be negative

[apanicker-nflx]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 3450

• 4 of 4 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.006%) to 70.086%

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Totals
Change from base Build 3439:	0.006%
Covered Lines:	11138
Relevant Lines:	15892

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💛 - Coveralls

[codecov]

Codecov Report

Merging #1426 into dev will increase coverage by <.01%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##               dev    #1426      +/-   ##
===========================================
+ Coverage     64.3%   64.31%   +<.01%     
- Complexity    3189     3192       +3     
===========================================
  Files          262      262              
  Lines        15580    15583       +3     
  Branches      1521     1523       +2     
===========================================
+ Hits         10019    10022       +3     
  Misses        4723     4723              
  Partials       838      838

Impacted Files	Coverage Δ	Complexity Δ
.../netflix/conductor/common/metadata/tasks/Task.java	81.33% <100%> (+0.25%)	93 <0> (+3)	⬆️

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