> there's no telling what "extra" Javascript (and thus overhead) might be inserted by the Typescript compiler
TypeScript doesn't do this. With only a few exceptions, the way to turn TypeScript into JavaScript is to remove the type annotations, which leaves you with JavaScript. This is an important design goal of TypeScript: it doesn't change your code, it's just JavaScript with types. Like Babel, TypeScript can be used to compile to earlier JS versions like ES5, but I'd consider that a misconfiguration in an environment like this.
Saying that TypeScript is slower than JavaScript is almost as silly as saying "C++ with comments is slower than C++ without comments". If you see a C++ program with comments that's slower than another one without comments, it's almost certainly because they're different programs, not because the comments have any effect. From a glance through your links, it seems likely that all of the running time differences are just because it's different code being run.
TypeScript doesn't do this. With only a few exceptions, the way to turn TypeScript into JavaScript is to remove the type annotations, which leaves you with JavaScript. This is an important design goal of TypeScript: it doesn't change your code, it's just JavaScript with types. Like Babel, TypeScript can be used to compile to earlier JS versions like ES5, but I'd consider that a misconfiguration in an environment like this.
Saying that TypeScript is slower than JavaScript is almost as silly as saying "C++ with comments is slower than C++ without comments". If you see a C++ program with comments that's slower than another one without comments, it's almost certainly because they're different programs, not because the comments have any effect. From a glance through your links, it seems likely that all of the running time differences are just because it's different code being run.