Update the outdated test_args of alpha-features testsuite of release branch jobs

[Rajalakshmi-Girish]

Due to outdated Regex for test_args,
Master branch is running ~138 tests ci-kubernetes-e2e-gci-gce-alpha-features
whereas, the release branches are running ONLY 53 tests. ci-kubernetes-e2e-gce-cos-k8sbeta-alphafeatures

The gcp alpha-feature release branch jobs have been running outdated the test_args and were not changed with time.

The current regex in test_args of master branch job defined at https://github.com/kubernetes/test-infra/blob/master/config/jobs/kubernetes/sig-cloud-provider/gcp/gcp-gce.yaml#L945 are applicable even for the release as old as1.29.

[k8s-ci-robot]

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[Rajalakshmi-Girish]

The test_args for alpha features test suite was last updated 3 years ago and hence the regex in master branch job will applicable for oldest stable branch in release jobs 1.29.(stable-3)

[Rajalakshmi-Girish]

@dims / @xmudrii Can you please review this?