wasm: fix FinalizationRegistry logic for Cloudflare Workers

This patch fixes FinalizationRegistry related logic for Cloudflare
Workers in wasm backend js post linker. Cloudflare Workers doesn't
support FinalizationRegistry, in this case we use a dummy
implementation that doesn't do anything.

(cherry picked from commit bea8ea4c)
(cherry picked from commit 0346e7b7)