When jsx is react-jsx or react-jsxdev, a JSX tag should imply the file is a module

[weswigham]

This is a followup for #39199 to track automatic moduleness for jsx-using files.

[weswigham]

I spoke with @RyanCavanaugh on this a little bit - accomplishing this would require contorting our parser API in very breaky ways (we cannot, at present, configure it based on compiler options); since we're not sure you can write a particularly useful JSX-containing file with no module markers at all, we're going to punt on this one for awhile. In the meantime, the standard workaround of "just add a module marker (like export {}) to the file" applies if anyone ever finds themselves in a situation where they've made a not-obviously-a-module file containing JSX using the new transforms.