Toolset update: VS 2019 16.9 Preview 3

[StephanTLavavej]

• azure-devops/provision-image.ps1
  • Obtain PsExec64.exe by downloading and extracting PSTools.zip, which is apparently recommended over directly downloading the executable.
  • Download and extract PowerShell 7.1.1 so we can pass -UseMinimalHeader to Start-Transcript, which reduces log verbosity.
  • Centralize common machinery in Function DownloadAndExtractZip.
  • Redact the AdminUserPassword when printing logs.
  • PsExec now requires the -i option when using -h. (Without it, the script fails with a difficult-to-understand error.)
  • Cleanup the extracted ZIP directories.
  • Update to Python 3.9.1.
  • Now that we're running in interactive mode, pip install prints useful information in the transcript (yay) but also a noisy progress bar that does us no good (because we only see the transcript when everything is done). So, run pip install with --progress-bar off.
  • Use bcdedit to enable test-signed kernel-mode drivers. (Works towards Kernel mode test harness #1421, untested here.)
• azure-devops/create-vmss.ps1
  • Set SuppressAzurePowerShellBreakingChangeWarnings; this noise has never been useful to us.
• README.md
  • Update VS, CMake, Ninja, Python versions. (CMake and Ninja were updated in Preview 3.)
• CMakeLists.txt
  • Require CMake 3.19. (We don't need anything from it yet - this is just the general principle of minimizing our support matrix.)
• azure-pipelines.yml
  • Use the new VMSS pool.
• tests/std/tests/P0220R1_optional/test.cpp
  • Work around (Microsoft-internal bug) VSO-1268140 "EDG: weirdness evaluating rvalue-qualified constexpr member function", reduced and reported by @CaseyCarter.

[miscco]

Awesome