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
```
testutil.delete_lambda_function(TEST_LAMBDA_NAME_RUBY)
class TestJavaRuntimes(LambdaTestBase):
    @classmethod
    def setUpClass(cls):
        cls.lambda_client = aws_stack.connect_to_service('lambda')
        
        if not os.path.exists(TEST_LAMBDA_JAVA):
            mkdir(os.path.dirname(TEST_LAMBDA_JAVA))
            download(TEST_LAMBDA_JAR_URL, TEST_LAMBDA_JAVA)
        
        
        cls.test_java_jar = load_file(TEST_LAMBDA_JAVA, mode='rb')
        cls.test_java_zip = testutil.create_zip_file(TEST_LAMBDA_JAVA, get_content=True)
        testutil.create_lambda_function(
            func_name=TEST_LAMBDA_NAME_JAVA,
            zip_file=cls.test_java_jar,
            runtime=LAMBDA_RUNTIME_JAVA8,
            handler='cloud.localstack.sample.LambdaHandler'
        )
        
        testutil.create_lambda_function(
            func_name=TEST_LAMBDA_NAME_JAVA_STREAM,
            zip_file=cls.test_java_jar,
            runtime=LAMBDA_RUNTIME_JAVA8,
            handler='cloud.localstack.sample.LambdaStreamHandler'
        )
        
        testutil.create_lambda_function(
            func_name=TEST_LAMBDA_NAME_JAVA_SERIALIZABLE,