Make executables thin wrappers around public API

#55326

• Public API of TypeScript is in typescript.js
  • Everything in tsserver.js depends on the same stuff as the API.
  • Same-ish is true of typingsInstaller.js
• Have a PR where these files just import parts of the API from each executable. tsserver.js and typingsInstaller.js just become <1000 lines of code on top of typescript.js.
• Great size reduction for our npm package size and editors that ship their own tsserver.js and typingsInstaller.js.
• Runtime speed does not seem to be impacted.
• What about tsc.js?
  • [experiment] make tsc use the public API #57703
  • tsc.js is roughly another a entry-point to our API.
  • You can get the same size reduction with this.
  • Significant regressions!
    • It's not just straight runtime, it's also start-up speed because of the extra code.
    • Different implementation of constructors with different orders?
      • It warrants an investigation.

Instantiation count in baselines

#57730

• We have no way to detect blow-ups of logic in the compiler other than our perf suite.
• But our test suite has a lot of esoteric work integrated into it.
• Idea is record a few metrics (assignability cache size, type count, instantiation count, symbol count) into our baseline outputs.
  • Rounded so that minor changes don't cause noise.
  • Have a threshold for each metric as well so not every test gets it.
• We like it.

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