benchmark,tools: fix napi benchmarks on GHA

[nigrosimone]

The GHA benchmark cannot run any napi/* benchmark: every run prints "Binding failed to load" (for example on #66395). Two reasons:

• the workflow builds Node, but never the benchmark addons
• the build uses --debug-node (the default of shell.nix), so process.features.debug is true and benchmark/common.js looks for the addon in build/Debug, while node-gyp builds it in build/Release

Now the workflow runs make bench-addons-build when the category has napi, and benchmark/common.js takes the build type from process.config, as test/common does.

Tested on my fork, napi/make_callback with the same code on both sides (x86_64-linux only): https://github.com/nigrosimone/node/actions/runs/36763821317

                              confidence improvement accuracy (*)   (**)  (***)
napi/make_callback n=1000000                  1.51 %       ±1.66% ±2.49% ±3.95%
napi/make_callback n=10000000          *      1.53 %       ±1.25% ±1.83% ±2.75%

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

[nodejs-github-bot]

Review requested:

• @nodejs/actions
• @nodejs/performance