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We have several Kinesis streams set up with event notifications that trigger lambdas.  When the LAMBDA_EXECUTOR is set to 'docker' and we send a large number or records to Kinesis, multiple Lambdas will execute, but currently they are failing to create with error:

```
Exception: Lambda process returned error status code: 1. Output:
time="2019-09-18T17:28:11Z" level=error msg="error getting events from daemon: net/http: request canceled" 
Error response from daemon: driver failed programming external connectivity on endpoint busy_sanderson (a78e45a41d0ce5b0d8bab6ff54344fc34fe2b4969f55bf568e753121abc8759e): Bind for 0.0.0.0:38763 failed: port is already allocated
```

I believe this is due to the new debug_java_port introduced with this PR https://github.com/localstack/localstack/pull/1523

With this change, you are setting the port in the constructor by using a method known to have a race condition (https://github.com/localstack/localstack/blob/master/localstack/utils/common.py#L354)
(https://gist.github.com/gabrielfalcao/20e567e188f588b65ba2)

This should be changed to ensure unique ports are being issued across all lambdas


DEFAULT_SERVICE_PORTS = localstack_client.config.get_service_ports()
BIND_HOST = '0.0.0.0'
if 'TEST_AWS_ACCOUNT_ID' not in os.environ:
    os.environ['TEST_AWS_ACCOUNT_ID'] = '000000000000'
TEST_AWS_ACCOUNT_ID = os.environ['TEST_AWS_ACCOUNT_ID']
LOCALSTACK_ROOT_FOLDER = os.path.realpath(os.path.join(os.path.dirname(os.path.realpath(__file__)), '..'))
LOCALSTACK_VENV_FOLDER = os.path.join(LOCALSTACK_ROOT_FOLDER, '.venv')
if not os.path.isdir(LOCALSTACK_VENV_FOLDER):
    
    LOCALSTACK_VENV_FOLDER = os.path.realpath(os.path.join(LOCALSTACK_ROOT_FOLDER, '..', '..', '..'))
PATH_USER_REQUEST = '_user_request_'
DOCKER_IMAGE_NAME = 'localstack/localstack'
CONFIG_UPDATE_PATH = '/?_config_'
ENV_INTERNAL_TEST_RUN = 'LOCALSTACK_INTERNAL_TEST_RUN'
APPLICATION_AMZ_JSON_1_0 = 'application/x-amz-json-1.0'
APPLICATION_AMZ_JSON_1_1 = 'application/x-amz-json-1.1'
APPLICATION_JSON = 'application/json'
APPLICATION_X_WWW_FORM_URLENCODED = 'application/x-www-form-urlencoded'
LAMBDA_TEST_ROLE = 'arn:aws:iam::%s:role/lambda-test-role' % TEST_AWS_ACCOUNT_ID
ELASTICSEARCH_JAR_URL = 'https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-6.7.0.zip'
ELASTICSEARCH_PLUGIN_LIST = ['analysis-icu', 'ingest-attachment', 'analysis-kuromoji',
 'mapper-murmur3', 'mapper-size', 'analysis-phonetic', 'analysis-smartcn', 'analysis-stempel', 'analysis-ukrainian']
ELASTICSEARCH_DELETE_MODULES = ['ingest-geoip']
DYNAMODB_JAR_URL = 'https://s3-us-west-2.amazonaws.com/dynamodb-local/dynamodb_local_latest.zip'
ELASTICMQ_JAR_URL = 'https://s3-eu-west-1.amazonaws.com/softwaremill-public/elasticmq-server-0.14.2.jar'
STS_JAR_URL = 'https://repo1.maven.org/maven2/com/amazonaws/aws-java-sdk-sts/1.11.14/aws-java-sdk-sts-1.11.14.jar'
STEPFUNCTIONS_ZIP_URL = 'https://s3.amazonaws.com/stepfunctionslocal/StepFunctionsLocal.zip'
API_ENDPOINT = os.environ.get('API_ENDPOINT') or 'https://api.localstack.cloud/v1'
MOTO_ACCOUNT_ID = '123456789012'