fix driver.IndexFromMachineName()

[prezha]

fixes #10820

as detailed in the issue's description, this pr fixes driver.IndexFromMachineName() and extends the tests to cover for noted edge cases

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: prezha, spowelljr
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[medyagh]

/ok-to-test

[minikube-pr-bot]

kvm2 Driver
error collecting results for kvm2 driver: timing run 0 with Minikube (PR 10821): timing cmd: [/home/performance-monitor/.minikube/minikube-binaries/10821/minikube start --driver=kvm2]: starting cmd: fork/exec /home/performance-monitor/.minikube/minikube-binaries/10821/minikube: exec format error
docker Driver
error collecting results for docker driver: timing run 0 with Minikube (PR 10821): timing cmd: [/home/performance-monitor/.minikube/minikube-binaries/10821/minikube start --driver=docker]: starting cmd: fork/exec /home/performance-monitor/.minikube/minikube-binaries/10821/minikube: exec format error

[medyagh]

Thank you, lgtm