[CI] Install WARP for CTS run

This means we use a reliable version rather than depending on whatever
the worker has installed.

.github/actions/install-warp/action.yml

@@ -20,6 +20,6 @@ runs:
         7z.exe e warp.zip -owarp build/native/bin/x64/d3d10warp.dll
 
         for dir in ${{ inputs.target-dirs }}; do
-          mkdir -p ${{ inputs.target-dirs }}
+          mkdir -p "$dir"
           cp -v warp/d3d10warp.dll "$dir"
         done

.github/workflows/cts.yml

@@ -63,6 +63,16 @@ jobs:
           debug = 1
           EOF
 
+      - name: (Windows) Install DXC
+        if: matrix.os == 'windows-2022'
+        uses: ./.github/actions/install-dxc
+
+      - name: (Windows) Install WARP
+        if: matrix.os == 'windows-2022'
+        uses: ./.github/actions/install-warp
+        with:
+          target-dirs: "target/debug"
+
       - name: (Linux) Install Mesa
         if: matrix.os == 'ubuntu-24.04'
         uses: ./.github/actions/install-mesa