Suppress diff for COS images

[melinath]

Resolves hashicorp/terraform-provider-google#8601. Upstreams hashicorp/terraform-provider-google#8602.

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Release Note Template for Downstream PRs (will be copied)

compute: added suppress diff func for cos-family disk images

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 3 files changed, 23 insertions(+))
Terraform Beta: Diff ( 3 files changed, 23 insertions(+))
TF Conversion: Diff ( 2 files changed, 18 insertions(+))

[modular-magician]

I have triggered VCR tests based on this PR's diffs. See the results here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=175379"

[melinath]

Test failures look unrelated.

[modular-magician]

I have triggered VCR tests in RECORDING mode for the following tests that failed during VCR: TestAccApiGatewayGateway_apigatewayGatewayBasicExampleUpdated|TestAccServiceUsageConsumerQuotaOverride_regionConsumerQuotaOverrideExample You can view the result here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=175467"