ci: Update to Python 3.11.3 in Windows jobs

Use the official embedded distribution `.zip` files,
but put copies at URLs we control.

.gitlab/ci/download_python3.cmake

@@ -1,41 +0,0 @@
-cmake_minimum_required(VERSION 3.17)
-
-set(version "3.8.6")
-set(sha256sum "376e18eef7e3ea467f0e3af041b01fc7e2f12855506c2ab2653ceb5e0951212e")
-set(dirname "python-${version}-embed-win-x86_64")
-set(tarball "${dirname}.tar.xz")
-
-# Download the file.
-file(DOWNLOAD
-  "https://cmake.org/files/dependencies/${tarball}"
-  ".gitlab/${tarball}"
-  STATUS download_status
-  EXPECTED_HASH "SHA256=${sha256sum}")
-
-# Check the download status.
-list(GET download_status 0 res)
-if (res)
-  list(GET download_status 1 err)
-  message(FATAL_ERROR
-    "Failed to download ${tarball}: ${err}")
-endif ()
-
-# Extract the file.
-execute_process(
-  COMMAND
-    "${CMAKE_COMMAND}"
-    -E tar
-    xzf "${tarball}"
-  WORKING_DIRECTORY ".gitlab"
-  RESULT_VARIABLE res
-  ERROR_VARIABLE err
-  ERROR_STRIP_TRAILING_WHITESPACE)
-if (res)
-  message(FATAL_ERROR
-    "Failed to extract ${tarball}: ${err}")
-endif ()
-
-# Move to a predictable directory.
-file(RENAME
-  ".gitlab/${dirname}"
-  ".gitlab/python3")

.gitlab/ci/python-env.ps1

@@ -1,4 +1,4 @@
 $pwdpath = $pwd.Path
-cmake -P .gitlab/ci/download_python3.cmake
+& "$pwsh" -File ".gitlab/ci/python.ps1"
 Set-Item -Force -Path "env:PATH" -Value "$pwdpath\.gitlab\python3;$env:PATH"
 python --version

.gitlab/ci/python.ps1

@@ -0,0 +1,30 @@
+$erroractionpreference = "stop"
+
+$version = "3.11.3"
+
+if ("$env:PROCESSOR_ARCHITECTURE" -eq "AMD64") {
+    $sha256sum = "7419B2E98516FBD0B66A1237B80187FFB21D32E47B4A4235C2D9D6379597070F"
+    $arch = "amd64"
+} elseif ("$env:PROCESSOR_ARCHITECTURE" -eq "ARM64") {
+    $sha256sum = "03BAD6A7C898FC8F693982437AAB6DB698107B82EA93F76424195AE2C161246C"
+    $arch = "arm64"
+} else {
+    throw ('unknown PROCESSOR_ARCHITECTURE: ' + "$env:PROCESSOR_ARCHITECTURE")
+}
+
+$filename = "python-$version-embed-$arch"
+$tarball = "$filename.zip"
+
+$outdir = $pwd.Path
+$outdir = "$outdir\.gitlab"
+$ProgressPreference = 'SilentlyContinue'
+Invoke-WebRequest -Uri "https://cmake.org/files/dependencies/internal/$tarball" -OutFile "$outdir\$tarball"
+$hash = Get-FileHash "$outdir\$tarball" -Algorithm SHA256
+if ($hash.Hash -ne $sha256sum) {
+    exit 1
+}
+
+Add-Type -AssemblyName System.IO.Compression.FileSystem
+[System.IO.Compression.ZipFile]::ExtractToDirectory("$outdir\$tarball", "$outdir\python3")
+Remove-Item "$outdir\python3\*._pth" # Avoid sys.path specific to embedded python.
+Remove-Item "$outdir\$tarball"