Set LIBCLANG_PATH instead of msys deletion in windows wotkflow (#30293)

until we get newer clang-sys due to https://github.com/KyleMayes/clang-sys/issues/150

.github/workflows/windows.yml

@@ -32,6 +32,10 @@ env:
   SHELL: /bin/bash
   CCACHE: "ccache"
   CARGO_TARGET_DIR: C:\\a\\servo\\servo\\target
+  # clang_sys will search msys path before Program Files\LLVM
+  # so we need to override this behaviour until we update clang-sys
+  # https://github.com/KyleMayes/clang-sys/issues/150
+  LIBCLANG_PATH: C:\\Program Files\\LLVM\\bin
 
 jobs:
   build:
@@ -55,8 +59,6 @@ jobs:
           Start-BitsTransfer -Source https://github.com/wixtoolset/wix3/releases/download/wix3111rtm/wix311-binaries.zip -Destination C:\\wix311-binaries.zip
           Expand-Archive C:\\wix311-binaries.zip -DestinationPath C:\\wix
           echo "C:\\wix" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
-      - name: Remove msys from PATH # see https://github.com/actions/runner-images/issues/2208
-        run: Remove-Item -LiteralPath "C:\msys64\" -Force -Recurse
       - name: ccache
         uses: hendrikmuhs/ccache-action@v1.2
       - name: Bootstrap