release-26.2.7-rc: roachtest: cluster_creation failed

roachtest.cluster_creation [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_Roachtests_RoachtestNightlyGcePrivateBazel/21516953?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_Roachtests_RoachtestNightlyGcePrivateBazel/21516953?buildTab=artifacts#/kv0/enc=false/nodes=3/cpu=96) on release-26.2.7-rc @ [d81e56ae7d745f070c6fbc5095a1eb2574616ebe](https://github.com/cockroachdb/cockroach/commits/d81e56ae7d745f070c6fbc5095a1eb2574616ebe):

```
test kv0/enc=false/nodes=3/cpu=96 failed: (test_runner.go:1027).func4: in provider: gce: BulkInsert failed for zone us-east1-d: BulkInsert operation failed for zone us-east1-d: gce create failed due to capacity in zone(s) [us-east1-d]: grpc: SERVICE UNAVAILABLE: errors:{code:"VM_MIN_COUNT_NOT_REACHED" message:"Requested minimum count of 3 VMs could not be created."} errors:{code:"ZONE_RESOURCE_POOL_EXHAUSTED_WITH_DETAILS" error_details:{help:{links:{description:"Troubleshooting documentation" url:"https://cloud.google.com/compute/docs/resource-error"}}} error_details:{localized_message:{locale:"en-US" message:"A n2d-custom-96-196608 VM instance is currently unavailable in the us-east1-d zone. Consider trying your request in another zone which has capacity to accommodate your request. Alternatively, you can try your request again with a different VM hardware configuration or at a later time. For more information, see the troubleshooting documentation."}} error_details:{error_info:{domain:"compute.googleapis.com" metadatas:{key:"attachment" value:""} metadatas:{key:"vmType" value:"n2d-custom-96-196608"} metadatas:{key:"zone" value:"us-east1-d"} metadatas:{key:"zonesAvailable" value:""} reason:"stockout"}} message:"The zone 'projects/crl-e2e-infra/zones/us-east1-d' does not have enough resources available to fulfill the request. '(resource type:compute)'."} [code 2/Unknown] [owner=test-eng]
```

Parameters:
- MetamorphicFilesystem=ext4
- MetamorphicVolumeType=pd-ssd
- cloud=gce
- coverageBuild=false
- cpu=96
- diskCount=0
- runtimeAssertionsBuild=false
Help

See: [roachtest README](https://github.com/cockroachdb/cockroach/blob/master/pkg/cmd/roachtest/README.md)

See: [How To Investigate \(internal\)](https://cockroachlabs.atlassian.net/l/c/SSSBr8c7)

/cc @cockroachlabs/test-eng

[This test on roachdash](https://roachdash.crdb.dev/?filter=status:open%20t:.*cluster_creation.*&sort=title+created&display=lastcommented+project) | [Improve this report!](https://github.com/cockroachdb/cockroach/tree/master/pkg/cmd/bazci/githubpost/issues)

Jira issue: CRDB-68424

Start with the roachtest README and the failure at test_runner.go:1027, then inspect the cluster_creation path and its GCE provider handling. Use the linked TeamCity log and artifacts to determine whether the capacity failure is reproducible and what concrete remediation is required; done should mean the test no longer fails for this capacity condition.

Written by the indexing model from the issue text.