Updates usage of co to async function in src/scintillator/index.spec.js

[ghost]

fixes #636

P.S. I'm glad to committing to Bemuse because I'm beatmania IIDX player in Japan :)

Changelog

Migrate part of the code from co to async functions

[ghost]

I think that we can ignore issues that is raised by codeclimate.
It saying "Similar blocks of code found in 2 locations. Consider refactoring" but they are obvious no problem.

[dtinth]

All the tests pass, so it seems to work! You are right about CodeClimate, we can ignore it for this change, since the code is objectively better than before, I’m approving this.

Thanks for contributing to Bemuse project! 😄

I will be playing songs in BOFXV (a big BMS event in Japan) and will be leaving some impressions. So maybe see you there! :D

[codecov-io]

Codecov Report

Merging #652 into master will increase coverage by 0.07%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #652      +/-   ##
==========================================
+ Coverage   80.91%   80.99%   +0.07%     
==========================================
  Files         156      156              
  Lines        4757     4782      +25     
  Branches      184      184              
==========================================
+ Hits         3849     3873      +24     
- Misses        859      860       +1     
  Partials       49       49

Impacted Files	Coverage Δ
src/scintillator/index.spec.js	99.6% <100%> (-0.4%)	⬇️

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[dtinth]

Closing as I just realized that this PR has already been cherry-picked into master — df0e85a