test: add semicolon after chunk size

The ABNF for chunk extensions as per RFC 7230 is

    chunk-ext      = *( ";" chunk-ext-name [ "=" chunk-ext-val ] )

    chunk-ext-name = token
    chunk-ext-val  = token / quoted-string

Add a semicolon after the chunk size for clarity.

This does not invalidate the test as it verifies that the HTTP parser
does not ignore chunk extensions.

PR-URL: #40487
Refs: https://grenfeldt.dev/2021/10/08/gunicorn-20.1.0-public-disclosure-of-request-smuggling
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-http-chunked-smuggling.js

@@ -23,7 +23,7 @@ function start() {
     'Host: localhost:8080\r\n' +
     'Transfer-Encoding: chunked\r\n' +
     '\r\n' +
-    '2 \n' +
+    '2;\n' +
     'xx\r\n' +
     '4c\r\n' +
     '0\r\n' +