sea: generate code cache with deserialized isolate
V8 now requires code cache to be compiled from an isolate with the same RO space layout as the one that's going to deserialize the cache, so for a binary built with snapshot, we need to compile the code cache using a deserialized isolate.
Drive-by: ignore "useCodeCache" when "useSnapshot" is true because the compilation would've been done during build time anyway in that case, and print a warning for it.