It is my understanding that setting an environment varialbe `TEST_AWS_ACCOUNT_ID` for localstack sets that as the AWS account for the user in localstack.

However, setting it does not actually change any ARNs. For example:

1. Start localstack using `TEST_AWS_ACCOUNT_ID="111111111111" DEBUG=1 localstack start`
2. Deploy anything with an ARN (in this example I deployed a lambda)
3. Check the ARN. Example output for lambda:
```json
$ awslocal lambda list-functions
{
    "Functions": [
        {
            "FunctionName": "localtest-local-hello",
            "FunctionArn": "arn:aws:lambda:us-east-1:000000000000:function:localtest-local-hello",
            "Runtime": "nodejs10.x",
            "Role": "test_role",
            "Handler": "handler.hello",
            "CodeSize": 3077,
            "Description": "",
            "Timeout": 6,
            "MemorySize": 1024,
            "LastModified": "2019-11-06T06:43:53.451+0000",
            "CodeSha256": "V77gR13o90ET7+XquXBBc3Rxr1qDu1bE7S+A0Wbx5ys=",
            "Version": "$LATEST",
            "TracingConfig": {
                "Mode": "PassThrough"
            },
            "RevisionId": "3d4ed679-c1a9-4b7e-ad9e-f27e8543c5e9"
        }
    ]
}
```

ARN is still 000000000000
return result[0] if result else None
        elif resource_type == 'ApiGateway::Resource':
            api_id = resource_props['RestApiId'] if resource else resource_id
            api_id = resolve_refs_recursively(stack_name, api_id, resources)
            parent_id = resolve_refs_recursively(stack_name, resource_props['ParentId'], resources)
            if not api_id or not parent_id:
                return None
            api_resources = aws_stack.connect_to_service('apigateway').get_resources(restApiId=api_id)['items']
            target_resource = list(filter(lambda res:
                res.get('parentId') == parent_id and res['pathPart'] == resource_props['PathPart'], api_resources))
            if not target_resource:
                return None
            path = aws_stack.get_apigateway_path_for_resource(api_id,
                target_resource[0]['id'], resources=api_resources)
            result = list(filter(lambda res: res['path'] == path, api_resources))
            return result[0] if result else None
        elif resource_type == 'ApiGateway::Deployment':
            api_id = resource_props['RestApiId'] if resource else resource_id
            api_id = resolve_refs_recursively(stack_name, api_id, resources)
            if not api_id:
                return None
            result = aws_stack.connect_to_service('apigateway').get_deployments(restApiId=api_id)['items']
            
            return result[0] if result else None
        elif resource_type == 'ApiGateway::Method':
            api_id = resolve_refs_recursively(stack_name, resource_props['RestApiId'], resources)
            res_id = resolve_refs_recursively(stack_name, resource_props['ResourceId'], resources)
            if not api_id or not res_id:
                return None
            res_obj = aws_stack.connect_to_service('apigateway').get_resource(restApiId=api_id, resourceId=res_id)