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
try:
        with open(os.devnull, 'w') as devnull:
            subprocess.check_output('docker ps', stderr=devnull, shell=True)
        return True
    except Exception:
        return False
def is_linux():
    try:
        out = subprocess.check_output('uname -a', shell=True)
        out = out.decode('utf-8') if isinstance(out, six.binary_type) else out
        return 'Linux' in out
    except subprocess.CalledProcessError:
        return False
LAMBDA_EXECUTOR = os.environ.get('LAMBDA_EXECUTOR', '').strip()
if not LAMBDA_EXECUTOR:
    LAMBDA_EXECUTOR = 'docker'
    if not has_docker():
        LAMBDA_EXECUTOR = 'local'
LAMBDA_FALLBACK_URL = os.environ.get('LAMBDA_FALLBACK_URL', '').strip()
CONFIG_ENV_VARS = ['SERVICES', 'HOSTNAME', 'HOSTNAME_EXTERNAL', 'LOCALSTACK_HOSTNAME', 'LAMBDA_FALLBACK_URL',
                   'LAMBDA_EXECUTOR', 'LAMBDA_REMOTE_DOCKER', 'LAMBDA_DOCKER_NETWORK', 'USE_SSL', 'DEBUG',
                   'KINESIS_ERROR_PROBABILITY', 'DYNAMODB_ERROR_PROBABILITY', 'PORT_WEB_UI', 'START_WEB',
                   'DOCKER_BRIDGE_IP', 'DEFAULT_REGION', 'LAMBDA_JAVA_OPTS', 'LOCALSTACK_API_KEY',
                   'LAMBDA_CONTAINER_REGISTRY']
for key, value in six.iteritems(DEFAULT_SERVICE_PORTS):
    clean_key = key.upper().replace('-', '_')
    CONFIG_ENV_VARS += [clean_key + '_BACKEND', clean_key + '_PORT', clean_key + '_PORT_EXTERNAL']
CONFIG_ENV_VARS += ['LOCALSTACK_' + v for v in CONFIG_ENV_VARS]
def ping(host):