ci/windows: Re-enable Windows build

The GStreamer-provided Windows build machine is back now.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11261>

.gitlab-ci.yml

@@ -539,7 +539,7 @@ arm_test:
     MESA_IMAGE_TAG: "2021-04-14-radv"
     MESA_UPSTREAM_IMAGE: "$CI_REGISTRY/$FDO_UPSTREAM_REPO/$MESA_IMAGE_PATH:${MESA_IMAGE_TAG}"
 
-.windows_build_vs2019:
+windows_build_vs2019:
   extends:
     - .container
     - .windows-docker-vs2019
@@ -956,7 +956,7 @@ meson-clang:
     CC: clang
     CXX: clang++
 
-.meson-windows-vs2019:
+meson-windows-vs2019:
   extends:
     - .build-windows
     - .use-windows_build_vs2019
@@ -969,7 +969,7 @@ meson-clang:
       - _build/meson-logs/*.txt
       - _install/
 
-.test-d3d12-windows:
+test-d3d12-windows:
   extends:
     - .build-windows
     - .use-windows_build_vs2019