feat: allow worker listen different port to support nginx sticky

[killagu]

Checklist

• [x] npm test passes
• [x] tests and/or benchmarks are included
• [x] commit message follows commit guidelines

Affected core subsystem(s)

Description of change

[codecov[bot]]

Codecov Report

Merging #94 into master will decrease coverage by 0.35%. The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #94      +/-   ##
==========================================
- Coverage   98.81%   98.46%   -0.36%     
==========================================
  Files           8        8              
  Lines         507      520      +13     
==========================================
+ Hits          501      512      +11     
- Misses          6        8       +2

Impacted Files	Coverage Δ
lib/app_worker.js	100% <100%> (ø)	:arrow_up:
lib/master.js	98.52% <100%> (-0.02%)	:arrow_down:
lib/utils/options.js	94.59% <0%> (-2.71%)	:arrow_down:
lib/utils/messenger.js	98.07% <0%> (-1.93%)	:arrow_down:

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[killagu]

@ngot Use ready callback to confirm worker is ready, instead of check listening port. When use nginxSticky mode, workers listen different port, check port will not work.