Cloudflare Request and response attribute asymmetry against Deno

[isaacs]

wrapRequestHandlerWithInit does not do two things wrapDenoRequestHandler does:

• set response headers as span attributes via httpHeadersToSpanAttributes(..., 'response')
• set isolationScope.setContext('response', { status_code })

Work item. Decide which behavior is correct and make the two match. If Cloudflare deliberately skips response headers for payload-size reasons, say so in a comment.

[linear-code]

JS-3577