In Windows 10 Insiders build 15019+ which will probably be released
mainstream somewhere this year Microsoft seems to have started being
stricter with API calls.

The call to `FreeConsole` just after `CreateProcess` is making Windows
treat the process
as an interactive process. In which case it tries to use the `Desktop
session` but fails resulting
in the cryptic error reported.

I don't understand why the call to `FreeConsole` was there and it
doesn't seem to be needed,
so removed.

This fixes #13411

Test Plan: ./validate, alternative just do anything with ghc which
requires compilation.

Reviewers: austin, bgamari, simonmar

Reviewed By: bgamari

Subscribers: rwbarton, thomie, #ghc_windows_task_force

Differential Revision: https://phabricator.haskell.org/D3319