Remove Windows test config file

We don't have a Windows CI anymore

config/config_test_windows.yml

@@ -1,13 +0,0 @@
----
-convert: false
-python: C:\Python36\python.exe
-avconv: C:\ProgramData\chocolatey\bin\ffmpeg.exe
-avconvVerbosity: fatal
-phantomjsDir: C:\ProgramData\chocolatey\bin\
-youtubedl: C:\Python36\Lib\site-packages\youtube_dl\__main__.py
-params:
-    - --no-warnings
-    - --ignore-errors
-    - --flat-playlist
-    - --restrict-filenames
-    - --no-check-certificate