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: https://github.com/nodejs/node/pull/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>