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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


return (data[:max_length] + '...') if len(data) > max_length else data
def parallelize(func, list, size=None):
    if not size:
        size = len(list)
    if size <= 0:
        return None
    pool = Pool(size)
    result = pool.map(func, list)
    pool.close()
    pool.join()
    return result
def isoformat_milliseconds(t):
    try:
        return t.isoformat(timespec='milliseconds')
    except TypeError:
        return t.isoformat()[:-3]
CACHE_FILE_PATTERN = CACHE_FILE_PATTERN.replace('_random_dir_', short_uid())