Use sorcery to merge sourcemaps between browserify and gulp-typescript (#9439)

* Use sorcery to merge sourcemaps between browserify and gulp-typescript

* Use shorthand

* Fix nit

* move comments, change loop into map

* Ahahaha, we should run code before pushing it

* Move conditional into call

scripts/types/ambient.d.ts

@@ -19,4 +19,6 @@ declare module "into-stream" {
         export function obj(content: any): NodeJS.ReadableStream
     }
     export = IntoStream;
-}
+}
+
+declare module "sorcery";