Convert @babel/parser to TypeScript

[JLHwung]

Q	A
Fixed Issues?	Closes #13370
Patch: Bug Fix?
Major: Breaking Change?
Minor: New Feature?
Tests Added + Pass?	Yes
Documentation PR Link
Any Dependency Changes?
License	MIT

In this PR we converts babel-parser to TypeScript, which marks an end of the transition from Flow (but not the end of improving the codebase typings). I tried to make this PR as small as possible. For those typing errors which can't be fixed at my first glance, I suppress them with @ts-expect-error. Hopefully we will remove most of them when we further improve the parser typings.

Significant changes:

• An Undone type marker is introduced for those intermediate AST nodes created by startNode

type Undone<T extends NodeType> = Omit<T, "type">;

Accessing the type property is a typing error so we are sure that we didn't do any type differentiation on unfinished AST nodes, otherwise the other properties are typed as the AST definitions in "babel-parser".

• For parser plugins, if we are calling this.someParserMethod which is not overridden in the plugin, we use super.someParserMethod instead.

Further Improvements that be landed in separate PRs:

• Cleanup the legacy Flow infrastructure
• Migrate @babel/parser AST types to @babel/types AST types
• Cleanup unnecessary @ts-expect-error comments

This PR revives #13370. I should also thank @zxbodya, who maintains the flowts which helps the transition process.

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/52583/

[liuxingbaoyu]

Amazing PR and at the same time CI is completely green, I like it very much!

[liuxingbaoyu]

export was added before the comment, which seems to be a problem with the automatic conversion.

update: I tried to pick the code block and it failed, see the code before and after here.

[nicolo-ribaudo]

Thanks, awesome! I pushed a commit undoing some minor format changes.