node-api: find the Environment once

[nigrosimone]

Without an async context, napi_make_callback goes through the public node::MakeCallback(), which looks up the Environment from the creation context of the callback on every call. The napi_env already knows it, so call into it directly, as the path with an async context does. node_napi_env__::node_env() also looked it up from the context on every call (also in can_call_into_js()): now it is found once, a napi_env lives as long as its Environment.

There was no benchmark for napi_make_callback, so this adds napi/make_callback_napi, a C addon calling it from a libuv timer like an I/O callback.

Draft because on main alone the gain is inside the noise (26.3.0 + #66316: -3.0% and +2.1%, no stars). With #66395 and #66500 underneath it is +15% (200 to 174 ns), compare.js, 30 runs, Linux x64, one core:

                                     confidence improvement accuracy (*)   (**)  (***)
napi/make_callback_napi n=1000000           ***     15.12 %       ±4.73% ±6.29% ±8.19%
napi/make_callback_napi n=10000000          ***     14.78 %       ±3.82% ±5.10% ±6.68%

The Node-API callback tests and the make-callback addon tests pass. Part of the plan in nodejs/performance#24.

Disclosure: I used Opus 5.5 (Max) as coding assistant

[nodejs-github-bot]

Review requested:

• @nodejs/gyp
• @nodejs/node-api
• @nodejs/performance