Add and fix tests running against real snippets.

[drasmart]

Changes

• Add _diagnoseUnconvertedCookies condition with replacement logging.
• Implement read access replacement for = document.cookie fragments.
  • Emulated by reconstructing so as not to affect the parsing code of every snippet.
• Make .complete's delegate reliably called back even if _updateEnabled is falsey.
• Add integration tests (C# project)
  • Using CLI tool from CXX repo to export snippets and check validity of cookie->session replacements.

Why

• storeEmptyValues writes a malformed session key where a snippet concatenates the cookie name #28