HTTP/2: socket leak with "return 444" in error_page (ticket #2455). Similarly to ticket #274 (7354:1812f1d79d84), early request finalization without calling ngx_http_run_posted_requests() resulted in a connection hang (a socket leak) if the 400 (Bad Request) error was generated in ngx_http_v2_state_process_header() due to invalid request headers and "return 444" was used in error_page 400.