Revert 'Testing: Workaround for b/255311117' (#946)
Revert 'Testing: Workaround for b/255311117' (#946)

The issue causing this was rolled back and sysprep-specialize-script-cmd
works again on Windows.

Keeping the `-oPreferredAuthentications=publickey` change from the
original commit because it could still be useful.
GoogleCloudPlatform/ops-agent,GoogleCloudPlatform/ops-agent