build,test: make building addon tests less fragile

* Get rid of recursive `make` when building the node binary.  An earlier
  commit makes GYP write out rules that we can use for proper dependency
  tracking.

* Use module name 'binding' in addons.md and addons-napi/*/binding.gyp.
  This massively simplifies the logic for generating the build rules.

* Check in auto-generated add-on tests from `doc/api/addons.md`.  The
  files change rarely and generating them dynamically causes no end of
  race conditions and special-casing during the build.

PR-URL: #17407
Reviewed-By: Richard Lau <riclau@uk.ibm.com>

.gitignore

@@ -74,7 +74,6 @@ ipch/
 /npm.wxs
 /tools/msvs/npm.wixobj
 /tools/msvs/genfiles/
-/test/addons/??_*/
 email.md
 deps/v8-*
 deps/icu