Windows builder making hangs

```
patrick-quist@ubpc:/opt/compiler-explorer/ce-ci$ ./build-image-win-builder.sh
The configuration is valid.
githubactions-runner.amazon-ebs.githubrunner: output will be in this color.

==> githubactions-runner.amazon-ebs.githubrunner: Prevalidating any provided VPC information
==> githubactions-runner.amazon-ebs.githubrunner: Prevalidating AMI Name: github-runner-win-builder-202608091714
==> githubactions-runner.amazon-ebs.githubrunner: Found Image ID: ami-05f902fcf398cfa8e
==> githubactions-runner.amazon-ebs.githubrunner: Creating temporary keypair: packer_6a78b55d-540f-8f9c-e2c0-2586a745463a
==> githubactions-runner.amazon-ebs.githubrunner: Launching a source AWS instance...
==> githubactions-runner.amazon-ebs.githubrunner: changing public IP address config to true for instance on subnet "subnet-690ed81e"
==> githubactions-runner.amazon-ebs.githubrunner: Instance ID: i-063764583848fcc9a
==> githubactions-runner.amazon-ebs.githubrunner: Waiting for instance (i-063764583848fcc9a) to become ready...
==> githubactions-runner.amazon-ebs.githubrunner: Waiting for auto-generated password for instance...
==> githubactions-runner.amazon-ebs.githubrunner: It is normal for this process to take up to 15 minutes,
==> githubactions-runner.amazon-ebs.githubrunner: but it usually takes around 5. Please wait.
==> githubactions-runner.amazon-ebs.githubrunner:
==> githubactions-runner.amazon-ebs.githubrunner: Password retrieved!
==> githubactions-runner.amazon-ebs.githubrunner: Using WinRM communicator to connect: 54.221.186.51
==> githubactions-runner.amazon-ebs.githubrunner: Waiting for WinRM to become available...
==> githubactions-runner.amazon-ebs.githubrunner: WinRM connected.
==> githubactions-runner.amazon-ebs.githubrunner: Connected to WinRM!
==> githubactions-runner.amazon-ebs.githubrunner: Provisioning with Powershell...
==> githubactions-runner.amazon-ebs.githubrunner: Provisioning with powershell script: /tmp/powershell-provisioner2969255086
```

Hangs forever.

Start with build-image-win-builder.sh and the Windows image's PowerShell provisioning step. Reproduce the run and inspect where provisioning stops after WinRM connects; done means the builder completes without hanging and produces the expected Windows image.

Written by the indexing model from the issue text.