Bug 1504376 [wpt PR 13866] - Delete appveyor.yml, a=testonly

Automatic update from web-platform-testsDelete appveyor.yml (#13866)

--

wpt-commits: 3051abb292fe91e74718f81c3dd1914c0ff53eb0
wpt-pr: 13866

testing/web-platform/tests/tools/appveyor.yml

@@ -1,32 +0,0 @@
-environment:
-  global:
-    HYPOTHESIS_PROFILE: ci
-  matrix:
-    - PYTHON: 'C:\\Python27'
-    - PYTHON: 'C:\\Python35'
-    - PYTHON: 'C:\\Python36'
-
-# Needed to make py.test believe our top level can be imported (we
-# otherwise end up in a wpt-tools directory, and of course you cannot
-# import a name including a hyphen in Python, so it ignores the fact
-# we have a __init__.py at the top level).
-clone_folder: 'C:\projects\wpttools'
-
-init:
-  - 'git config --global core.autocrlf true'
-
-install:
-  - 'rm .git\index'
-  - 'git reset --hard'
-  - 'SET PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%'
-  - 'git submodule update --init --recursive'
-  - 'python.exe -m pip install tox codecov'
-
-build: off
-
-test_script:
-  - 'tox -e py'
-
-on_success:
-  - 'coverage combine'
-  - 'codecov'