feat: impl parallel app for mocha parallel mode

[killagu]

• use mochaGlobalSetup/mochaGlobalTeardown to setup agent in mocha master process.
• bootstrap app without agent to aviod port conflict.

Checklist

• npm test passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

Description of change

[codecov]

Codecov Report

Base: 92.32% // Head: 86.01% // Decreases project coverage by -6.31% ⚠️

Coverage data is based on head (35b0a71) compared to base (fbbd8af).
Patch coverage: 57.18% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #130      +/-   ##
==========================================
- Coverage   92.32%   86.01%   -6.32%     
==========================================
  Files          19       23       +4     
  Lines        1915     2295     +380     
  Branches      360      380      +20     
==========================================
+ Hits         1768     1974     +206     
- Misses        147      321     +174     

Impacted Files	Coverage Δ
lib/parallel/app.js	30.70% <30.70%> (ø)
lib/parallel/util.js	39.24% <39.24%> (ø)
lib/utils.js	81.57% <63.15%> (-18.43%)	⬇️
lib/parallel/agent.js	85.18% <85.18%> (ø)
bootstrap.js	92.10% <88.88%> (-1.65%)	⬇️
lib/parallel/agent_register.js	100.00% <100.00%> (ø)
lib/request_call_function.js	64.00% <0.00%> (-20.00%)	⬇️

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[fengmk2]

@killagu 你发个版本，重新跑一下 egg-bin 应该就能过了。

[killagu]

+ egg-mock@5.1.0