Delete outdated check_license script (#55425)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/55425

See blame — this script lints for a `"PATENTS"` string inside any Git changes, which should not occur any more.

> D7119356 (8 years ago)
>
> [react-native][PR] Check PATENTS does not creep into files
>
> Summary:
> Some files have crept into the repo with the old license header. These are usually from PRs that were opened prior to the re-licensing of the project.

Changelog: [Internal]

Reviewed By: cortinico

Differential Revision: D92417808

fbshipit-source-id: 36e3507f835fe5df99644eb1a47cdc60fa68f88c