docs(typescript-estree): remove defunct Build/Test Commands from README

[sosukesuzuki]

I ran npm run ast-alignment-tests to run AST Alignment Tests, but the command does not seem to exist already.

This PR removes documentations for commands that do not already exist from README.

[typescript-eslint]

Thanks for the PR, @sosukesuzuki!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

---

🙏 Please, if you or your company is finding typescript-eslint valuable, help us sustain the project by sponsoring it transparently on https://opencollective.com/typescript-eslint. As a thank you, your profile/company logo will be added to our main README which receives thousands of unique visitors per day.

[codecov]

Codecov Report

Merging #2650 into master will decrease coverage by 0.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2650      +/-   ##
==========================================
- Coverage   92.84%   92.80%   -0.05%     
==========================================
  Files         294      293       -1     
  Lines        9664     9604      -60     
  Branches     2711     2711              
==========================================
- Hits         8973     8913      -60     
  Misses        326      326              
  Partials      365      365              

Flag	Coverage Δ
#unittest	92.80% <ø> (-0.05%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
packages/scope-manager/src/lib/index.ts

[bradzacher]

oops - thanks for cleaning this up!