build: refactor GitHub Action jobs

[malept]

• I have read the contribution documentation for this project.
• I agree to follow the code of conduct that this project follows, as appropriate.
• The changes have sufficient test coverage (if applicable).
• The testsuite passes successfully on my local machine (if applicable).

Summarize your changes:

Instead of splitting up tests by node installer, the tests are effectively split up by "integration" (i.e., api_spec_slow in the core module) and "non-integration". The node installer specific tests are run in the same job, since both npm and yarn are always installed.

In my testing, this makes the suite run a couple of minutes faster on average.

[codecov]

Codecov Report

Merging #1875 into master will increase coverage by 2.44%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1875      +/-   ##
==========================================
+ Coverage   70.28%   72.73%   +2.44%     
==========================================
  Files          74       74              
  Lines        2191     2208      +17     
  Branches      414      415       +1     
==========================================
+ Hits         1540     1606      +66     
+ Misses        465      443      -22     
+ Partials      186      159      -27     

Impacted Files	Coverage Δ
packages/api/cli/src/util/check-system.ts	73.68% <0.00%> (-5.27%)	⬇️
packages/api/core/src/util/electron-version.ts	93.65% <0.00%> (-1.59%)	⬇️
packages/api/core/src/api/start.ts	64.47% <0.00%> (ø)
packages/maker/zip/src/MakerZIP.ts	100.00% <0.00%> (ø)
packages/api/core/src/api/publish.ts	69.73% <0.00%> (ø)
packages/api/core/src/util/rebuild.ts	92.85% <0.00%> (ø)
packages/utils/async-ora/src/index.ts	100.00% <0.00%> (ø)
packages/template/base/src/BaseTemplate.ts	100.00% <0.00%> (ø)
packages/utils/async-ora/src/ora-handler.ts	90.00% <0.00%> (ø)
packages/api/core/src/util/plugin-interface.ts	31.11% <0.00%> (ø)
... and 21 more

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