test: assert that invalidcmd throws error code

Update invalidcmd test case in test-child-process-spawn-typeerror to
assert on specific expected error code.

PR-URL: https://github.com/nodejs/node/pull/23942


Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>