Run parser tests from the official TypeScript parser

[nicolo-ribaudo]

Q	A
Fixed Issues?	Closes #6104
Tests Added + Pass?	Yes
Any Dependency Changes?	Yes, dev dependency
License	MIT

The two commits can/should be reviewed one by one.

In the first commit, I abstracted the logic to run external Babel tests: I now that abstractions can introduce bugs, but I didn't want to have three different files to do basically the same thing 😛

In the second commit I added the tests from https://github.com/Microsoft/TypeScript. The whitelist is so big because many invalid JavaScript programs are accepted by the TypeScript parser without any error (because they report them in the typechecker, which is too strict compared to @babel/parser).

cc @babel/typescript

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/11582/

[KFlash]

@nicolo-ribaudo Regarding the whitelist file. There are plenty of cases where the Babel TS parser doesn't fail / pass as it should which isn't related to the type checker..

Just to mention a few ... The current dynamic import isn't equal to what TS does, the subtract type node should also accept type reference and not only literal. See TS source.
There are other cases as well related to the class and function implementation etc.

I think I discovered around 60 different cases in total.

[nicolo-ribaudo]

Yeah I know, but a significant part of them are for things like duplicate declarations, or invalid modifiers (e.g. static const x = 2 as a class field)

[JLHwung]

It will fail on make -j test-typescript-ci since test-typescript depends on bootstrap. Could you rebase on master?

[JLHwung]

nit: code-like comments should be removed.

[JLHwung]

Great work!

[nicolo-ribaudo]

https://travis-ci.com/babel/babel/jobs/262389187