Incorrect no-shadow-variable failures when using mockTypeScriptVersion

[andyrooger]

With 0.9.9 released, I've finally got around to replacing my local workaround for #58 with the proper fix - turning on mockTypeScriptVersion.

Unfortunately this results in almost every variable being incorrectly flagged as failing the no-shadow-variable rule. That's ~58000 errors in the project I'm working on. This is something I didn't see when testing the original PR, so I'm not sure what's changed.

To reproduce:

• Set up tslint-language-service in Visual Studio 2017 with TypeScript Tools for Microsoft Visual Studio installed
• Make sure the typescript version in the project's node_modules is different to the one included in the VS TypeScript Tooling
• Turn on the mockTypeScriptVersion option in the plugin
• Open a TS file in VS

This should result in most variables (especially any imports or exports) being flagged as shadowing themselves.

It looks like this is caused by loading tslint twice (require then mockRequire.reRequire), though I'm not sure why this is the case.