drop node16 support

[Kikobeats]

• drop @ungap/structured-clone
• drop structuredClone
• drop undici?
• drop blob-polyfill
• drop formdata-node
• drop getSetCookie fallback
• drop toToReadable
  • introduced by: feat(node-utils): introduces @edge-runtime/node-utils to run edge compliant code in Node.js environment #219.
  • use stream.Readable.fromWeb instead.
• remove conditional assertions (find for process.version)

  • edge-runtime/packages/integration-tests/tests/blob.test.ts

    Line 1 in c2d9c3c

    const test18 = process.version.startsWith('v18.') ? test : test.skip

  • edge-runtime/packages/integration-tests/test/body.test.ts

    Line 1 in 87a5b5e

    const testOrSkip =