A few cleanups for the windows build

* Since we're no longer building with a newer gcc under msys2 we no longer
need to copy those specific files into our tree.
* Update the dictionaries to a new build.

Testing Done:
Built on windows and installed the online and offline installers without issue including downloading the en_US dictionary.

Also verified that the crash on exit was no more.

Reviewed at https://reviews.imfreedom.org/r/2976/