Create tests for 2284 in Tempesta FW

[EvgeniiMekhanik]

Create tests to check that Tempesta FW drop connection data and free up memory as soon as possible after receiving TCP FIN/TCP RST from the client. It;s better to write the new go program. Cases:

• Client opens 100 connections and sens small requests to Tempesta FW. Backend (deproxy server) sends not full (big) response. Client sends FIN/RST (both cases should be covered) to Tempesta FW. Do it in the loop.
• Same as previous but use big requests/small responses.
• Client opens 100 connections and sends small requests to Tempesta FW. Backend (deproxy server) sends a very big response. After receiving headers, stop read response on the client side. Send FIN/RST (both cases should be covered) from the client. Do it in the loop.
• Same as previous but only for http2. Initiate connection with zero HTTP2 window.
• Client make a request to a large response (>=64KB). Tempesta forwards the request to deproxy server, but it returns response with TCP segmentation (~1KB) and delay between chunks (~1 sec). Then the client brokes connection using FIN/TCP. Expected result: TempestaFW free up memory (drop this request from queue to server + drop response data from the server or drop this connection)