Dump kernel logs after running the tests in the MSHV workflow to help
debug failures.
In addition to getting the kernel logs using `dmesg` also use AzCli to
retrieve the serial console logs. If the VM is hung or panicked, the
workflow would be unable to SSH into it and execute `dmesg`. In this
case the serial console logs would be helpful.
Signed-off-by: Anirudh Rayabharam <anrayabh@microsoft.com>
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