Dev experience

[cspotcode]

Changes

On CI, test that node and TS versions are correct and match test matrix, in case CI scripts have a flaw
switch to yarn (was using npm)
run CI stuff on node 18 (was 16)
turn off some text matrix entries:

• node 14.13.0
• node 16.11.1
• TS 4.0 on node 16 (still runs on node 14)
  yarn lint-fix -> yarn fmt

[codecov]

Codecov Report

Merging #1854 (124df8e) into main (6ab696c) will decrease coverage by 35.48%.
The diff coverage is n/a.

❗ Current head 124df8e differs from pull request most recent head d9cc512. Consider uploading reports for the commit d9cc512 to get more accurate results

Impacted Files	Coverage Δ
dist-raw/node-internal-errors.js	21.73% <0.00%> (-73.92%)	⬇️
src/repl.ts	9.50% <0.00%> (-70.59%)	⬇️
dist-raw/node-internal-modules-cjs-helpers.js	34.78% <0.00%> (-65.22%)	⬇️
dist-raw/node-internal-modules-cjs-loader.js	8.36% <0.00%> (-63.50%)	⬇️
src/node-module-type-classifier.ts	33.33% <0.00%> (-58.34%)	⬇️
dist-raw/node-primordials.js	17.39% <0.00%> (-56.53%)	⬇️
src/module-type-classifier.ts	41.66% <0.00%> (-54.17%)	⬇️
src/ts-transpile-module.ts	27.45% <0.00%> (-49.02%)	⬇️
dist-raw/node-internalBinding-fs.js	47.36% <0.00%> (-47.37%)	⬇️
src/cjs-resolve-hooks.ts	33.33% <0.00%> (-40.01%)	⬇️
... and 19 more

[cspotcode]

Removed the following from OP; will track with a follow-up PR #1857

• testability improvements?
  • allow configuration tests to skip executing code
  • service.getInternalConfiguration()