As an enhancement to https://github.com/localstack/localstack/pull/1194

It would be really helpful to send the Lambda name, either as data, a header, or as part of the URL.

At code location: https://github.com/localstack/localstack/blob/03c6f4bf250edd18eb818ed65090f508636b0bff/localstack/services/awslambda/lambda_api.py#L696

I can likely open a PR to handle this given some feedback on the feature and potential design.

Right now all I see is the following (using `npx http-echo-server`):
```
[socket#8] event: data
--> POST / HTTP/1.1
--> Host: 192.168.1.x:3000
--> User-Agent: python-requests/2.22.0
--> Accept-Encoding: gzip, deflate
--> Accept: */*
--> Connection: keep-alive
--> Content-Length: 9
--> Content-Type: application/x-www-form-urlencoded
-->
-->
[socket#8] event: data
--> Name=test
```
TEST_LAMBDA_NAME_DOTNETCORE2 = 'test_lambda_dotnetcore2'
TEST_LAMBDA_NAME_DOTNETCORE31 = 'test_lambda_dotnetcore31'
TEST_LAMBDA_NAME_CUSTOM_RUNTIME = 'test_lambda_custom_runtime'
TEST_LAMBDA_NAME_JAVA = 'test_lambda_java'
TEST_LAMBDA_NAME_JAVA_STREAM = 'test_lambda_java_stream'
TEST_LAMBDA_NAME_JAVA_SERIALIZABLE = 'test_lambda_java_serializable'
TEST_LAMBDA_NAME_ENV = 'test_lambda_env'
TEST_LAMBDA_ECHO_FILE = os.path.join(THIS_FOLDER, 'lambdas', 'lambda_echo.py')
TEST_LAMBDA_SEND_MESSAGE_FILE = os.path.join(THIS_FOLDER, 'lambdas', 'lambda_send_message.py')
TEST_LAMBDA_PUT_ITEM_FILE = os.path.join(THIS_FOLDER, 'lambdas', 'lambda_put_item.py')
TEST_LAMBDA_START_EXECUTION_FILE = os.path.join(THIS_FOLDER, 'lambdas', 'lambda_start_execution.py')
TEST_LAMBDA_FUNCTION_PREFIX = 'lambda-function'
TEST_SNS_TOPIC_NAME = 'sns-topic-1'
MAVEN_BASE_URL = 'https://repo.maven.apache.org/maven2'
TEST_LAMBDA_JAR_URL = '{url}/cloud/localstack/{name}/{version}/{name}-{version}-tests.jar'.format(
    version=LOCALSTACK_MAVEN_VERSION, url=MAVEN_BASE_URL, name='localstack-utils')
TEST_LAMBDA_LIBS = [
    'localstack', 'localstack_client', 'requests', 'psutil', 'urllib3', 'chardet', 'certifi', 'idna', 'pip', 'dns'
]
def _run_forward_to_fallback_url(url, num_requests=3):
    lambda_client = aws_stack.connect_to_service('lambda')
    config.LAMBDA_FALLBACK_URL = url
    try:
        for i in range(num_requests):
            lambda_client.invoke(FunctionName='non-existing-lambda-%s' % i,
                                 Payload=b'{}', InvocationType='RequestResponse')
    finally:
        config.LAMBDA_FALLBACK_URL = ''
class LambdaTestBase(unittest.TestCase):
    def check_lambda_logs(self, func_name, expected_lines=[]):