v2.7.11 stop treating a comma in a URL as a list separator, remove dead code.

urlMeta.rewrite diverted any string containing a comma to the text-oriented
fallback, which returns a bare absolute http(s) URL unchanged. A lone URL with
a comma therefore went straight to the origin instead of through the proxy:
CDN combo paths (??a.js,b.js) and comma-separated query values (filter=a,b,c).

Also fixes the explicit-port match, which scanned the whole URL string and
turned any path or query ending in ":" into a port.