azure ci: install tar and xz with pacman

Author: andrewrk

ci/azure/windows_msvc_install

@@ -4,7 +4,7 @@ set -x
 set -e
 
 pacman -Su --needed --noconfirm
-pacman -S --needed --noconfirm wget p7zip python3-pip
+pacman -S --needed --noconfirm wget p7zip python3-pip tar xz
 pip install s3cmd
 wget -nv "https://ziglang.org/deps/llvm%2bclang%2blld-10.0.0-x86_64-windows-msvc-release-mt.tar.xz"
 tar xf llvm+clang+lld-10.0.0-x86_64-windows-msvc-release-mt.tar.xz