Should we fallback to ts.transpileModule whenever we get "Emit skipped"?

Seems like a bit of a hack, but it means certain situations "just work." If the file is statically imported, then it's already being typechecked. The only limitation is that transpileOnly needs isolatedModules, so if projects rely on rare things like inlined const enumeration values, that'll fail. But otherwise seems like a win.

Would fix #693