child_process: add ChildProcess 'spawn' event
The new event signals that the subprocess has spawned successfully and no 'error' event will be emitted from failing to spawn.
Fixes: https://github.com/nodejs/node/issues/35288
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
tests and/or benchmarksare included -
documentation is changed oradded -
commit message follows commit guidelines
Big thanks to @bnoordhuis for his guidance & the actual changes to lib/
!