Use `module: node12` in tsconfig.json; supports not transpiling `import() / dynamic import` for CommonJS code

[typhonrt]

A most recent merged PR for Typescript now better supports Node 12. In particular there is no need for the "semi-hack" used in module-loader.ts.

You can see discussion here and the PR here. When the latest Typescript version is available w/ this PR I'll look into adding module: node12 to tsconfig.json and verify that import dynamic works correctly with the Oclif core build and remove the workaround.

A blog post about the Typescript 4.5 beta.

[mdonnalley]

@typhonrt Is this work that you're still interested in doing? Or can we close this?

[git2gus]

This issue has been linked to a new work item: W-13832724