Add hostNodeName to workflow.failures

# Summary

I'm analyzing workflow.failure to get the message of workflow failure. But sometimes workflow step failed due to node failure, e.g. node OOM, node networkf issue. I want workflow.failures to support posting hostNodeName. As I see, it's simple to add it in https://github.com/argoproj/argo-workflows/blob/master/workflow/controller/operator.go#L105 as we could already get [node.hostNodeName](https://github.com/argoproj/argo-workflows/blob/cda7cd46a7ba6632cf6cb9ce034dabd48a491595/workflow/controller/operator.go#L969) here.

# Use Cases

The `workflow.failures` variable is provided to exit-handler step for debug. Since step failed due to node issue sometimes, the `workflow failures` need to contain a `hostNodeName` field.

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**Message from the maintainers**:

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Start in workflow/controller/operator.go around lines 105 and 969 to trace how workflow.failures is assembled and where node.hostNodeName is available. Confirm that the resulting failure data exposed to the exit-handler includes hostNodeName for node-related failures.

Written by the indexing model from the issue text.