ci: use python from the correct path

Apparently the old path we were using for Python 2 on Windows was not
documented, and eventually got removed. This switches our CI to use the
correct path.

src/ci/scripts/install-msys2-packages.sh

@@ -13,6 +13,7 @@ if isWindows; then
     # one way or another. The msys interpreters seem to have weird path conversions
     # baked in which break LLVM's build system one way or another, so let's use the
     # native version which keeps everything as native as possible.
-    cp C:/Python27amd64/python.exe C:/Python27amd64/python2.7.exe
-    ciCommandAddPath "C:\\Python27amd64"
+    python_home="C:/hostedtoolcache/windows/Python/2.7.17/x64"
+    cp "${python_home}/python.exe" "${python_home}/python2.7.exe"
+    ciCommandAddPath "C:\\hostedtoolcache\\windows\\Python\\2.7.17\\x64"
 fi