fix(engine): support Node 10 query parsing

[tianrking]

Summary

Fixes #5527.

Engine.IO advertises support for Node.js 10.2+, but both the standard HTTP server and the uWebSockets server parsed query strings with Object.fromEntries(), which was only added in Node.js 12. A polling handshake therefore threw before validation on supported Node 10 deployments.

Replace those calls with a shared URLSearchParams parser that uses Object.defineProperty. It preserves the previous last-value-wins behavior for duplicate keys and keeps __proto__ as an ordinary own property rather than mutating the query object's prototype.

Tests

• Added a regression test that removes Object.fromEntries and verifies a polling handshake still succeeds.
• npm run compile --workspace=engine.io
• npx mocha --bail --exit test/server.js --grep 'without Object.fromEntries'
• npx prettier --check lib/server.ts lib/userver.ts test/server.js
• npx mocha --bail --exit reached 90 passing tests (including the new regression and existing __proto__ coverage); it then hit an existing xhr timeout after npm ci --ignore-scripts left the optional HTTP/3 native module unavailable on Windows.