src/compiler/parser.ts exports function with return type of private interface

Export ReferencePathMatchResult interface to fix 'error TS4060: Return type of exported function has or is using private name' when generating declarations from `src/compiler/*.ts`.

See #1111

Tests run just fine.
>   29974 passing (2m)
That makes sense structurally, but parser.ts explicitly calls the function `createTypeChecker` on line 4298, which is defined in `checker.ts` (line 64). The reason why it compiles successfully in the `jake local` call is because `checker.ts` is explicitly included in the `tsc` command line arguments.

You can see the issue by running:
```sh
node bin/tsc --out tmp.js src/compiler/parser.ts
```
> src/compiler/parser.ts(4298,50): error TS2304: Cannot find name 'createTypeChecker'.