Fix zone specification in HdT tests

[sunnylovestiramisu]

What type of PR is this?

/kind failing-test

What this PR does / why we need it:
The zone specification was mistakenly added, HdT is available in both the two test zones:

➜  ~ gcloud compute disk-types list --filter="zone:( us-east4-a)" --project xxxxxxx
NAME                  ZONE        VALID_DISK_SIZES
hyperdisk-extreme     us-east4-a  64GB-65536GB
hyperdisk-throughput  us-east4-a  2048GB-32768GB
local-ssd             us-east4-a  375GB-375GB
pd-balanced           us-east4-a  10GB-65536GB
pd-extreme            us-east4-a  500GB-65536GB
pd-ssd                us-east4-a  10GB-65536GB
pd-standard           us-east4-a  10GB-65536GB
➜  ~ gcloud compute disk-types list --filter="zone:( us-east4-c)" --project xxxxxxx
NAME                  ZONE        VALID_DISK_SIZES
hyperdisk-extreme     us-east4-c  64GB-65536GB
hyperdisk-throughput  us-east4-c  2048GB-32768GB
local-ssd             us-east4-c  375GB-375GB
pd-balanced           us-east4-c  10GB-65536GB
pd-extreme            us-east4-c  500GB-65536GB
pd-ssd                us-east4-c  10GB-65536GB
pd-standard           us-east4-c  10GB-65536GB

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Fix zone specification in HdT tests

[sunnylovestiramisu]

/assign @amacaskill

[amacaskill]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: amacaskill, sunnylovestiramisu

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[sunnylovestiramisu]

panic: test timed out after 20m0s

/retest

[sunnylovestiramisu]

/cherry-pick release-1.11

[k8s-infra-cherrypick-robot]

@sunnylovestiramisu: new pull request created: #1341

In response to this:

/cherry-pick release-1.11

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