Remove an unnecessary check for "_map" as we no longer emit them.
Remove an unnecessary check for "_map" as we no longer emit them.

hippich/typescript,mbebenita/shumway.ts,mbrowne/typescript-dci,mbrowne/typescript-dci,fdecampredon/jsx-typescript-old-version,mbebenita/shumway.ts,popravich/typescript,mbebenita/shumway.ts,popravich/typescript,popravich/typescript,mbrowne/typescript-dci,hippich/typescript,mbrowne/typescript-dci,fdecampredon/jsx-typescript-old-version,hippich/typescript,fdecampredon/jsx-typescript-old-version