Fix windows build IsCorruptedMnt not implemented

[wongma7]

Is this a bug fix or adding new feature?

What is this PR about? / Why do we need it? as seen in our master branch CI https://github.com/kubernetes-sigs/aws-ebs-csi-driver/runs/3508198636 the windows build fails.

this was not cauhgt by PR CI because no PR CI exercises the windows build, I've assigned myself a task to fix this: #1046

After this merges, what I plan to do is retag 1.1.4 and 1.2.1 to trigger another image rebuild. It is not pretty but, since no images for 1.1.4 or 1.2.1 got pushed to docker hub/gcr there is no harm.

edit: 1.1.4 and 1.2.1 failed for a different reason than master branch, they timed out unexpectedly after 1hr: https://prow.k8s.io/view/gs/kubernetes-jenkins/logs/aws-ebs-csi-driver-push-images/1433833154082246656
the 1.1.3 build succeeded after 45 mins: https://prow.k8s.io/view/gs/kubernetes-jenkins/logs/aws-ebs-csi-driver-push-images/1418730174391783424

What testing is done?
$ make windows/amd64
CGO_ENABLED=0 GOOS=windows GOARCH=amd64 go build -mod=vendor -ldflags "-X github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/driver.driverVersion=v1.2.0 -X github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/cloud.driverVersion=v1.2.0 -X github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/driver.gitCommit=3b6a45aace77298ad774fba267096aa7d0d3a3c8 -X github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/driver.buildDate=2021-09-08T20:27:35+00:00 -s -w" -o bin/aws-ebs-csi-driver.exe ./cmd/

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[vdhanan]

/lgtm