## Issue description
When creating a CloudFormation stack, the `CreationDate` is always `2011-05-23T15:47:44Z`

## Steps to reproduce
1. Prepare a CloudFormation file, for example
```yml
AWSTemplateFormatVersion: 2010-09-09
Description: My Stack
Resources:
  LambdaCodeBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName: my-bucket
```
2. Create a new stack based on this file, I used the command:
```bash
awslocal cloudformation create-stack --stack-name gch --template-body file://stack.yml
```
3. List all the created stacks and confirm the `CreationDate` is not a present date
```
awslocal cloudformation list-stacks
```
```
{
    "StackSummaries": [
        {
            "StackId": "arn:aws:cloudformation:us-east-1:000000000000:stack/stack/27187f13-a645-40a0-8788-62d502358216",
            "StackName": "stack",
            "TemplateDescription": "My Stack",
            "CreationTime": "2011-05-23T15:47:44Z",
            "StackStatus": "CREATE_COMPLETE"
        }
    ]
}
```
except Exception as e:
                if 'ResourceNotFoundException' in str(e):
                    return get_table_not_found_error()
                raise
        elif action == '%s.DescribeTable' % ACTION_PREFIX:
            
            table_names = ddb_client.list_tables()['TableNames']
            if to_str(data['TableName']) not in table_names:
                return get_table_not_found_error()
        elif action == '%s.DeleteTable' % ACTION_PREFIX:
            
            table_names = ddb_client.list_tables()['TableNames']
            if to_str(data['TableName']) not in table_names:
                return get_table_not_found_error()
        elif action == '%s.BatchWriteItem' % ACTION_PREFIX:
            existing_items = []
            for table_name in sorted(data['RequestItems'].keys()):
                for request in data['RequestItems'][table_name]:
                    for key in ['PutRequest', 'DeleteRequest']:
                        inner_request = request.get(key)
                        if inner_request:
                            existing_items.append(find_existing_item(inner_request, table_name))
            ProxyListenerDynamoDB.thread_local.existing_items = existing_items
        elif action == '%s.TransactWriteItems' % ACTION_PREFIX:
            existing_items = []
            for item in data['TransactItems']:
                for key in ['Put', 'Update', 'Delete']:
                    inner_item = item.get(key)
                    if inner_item:
                        existing_items.append(find_existing_item(inner_item))