Experimental `node_api_nogc_env` is not stripped

[legendecas]

Ref: https://github.com/nodejs/node-api-headers/blob/1294543dc1487389acc9cf2371572f57e1eb797d/include/js_native_api_types.h#L46-L53

All other NAPI_EXPERIMENTAL apis were stripped, but node_api_nogc_env and node_api_nogc_finalize were not.

If NAPI_EXPERIMENTAL is defined, node_api_post_finalizer is missing for node_api_nogc_finalize callbacks.