build: make build-addons errors fail the build

The `build-addons` makefile target runs `tools/doc/addon-verify.js` and
then uses `touch` to update a timestamp file. Unconditionally calling
`touch` was losing the exit code from `tools/doc/addon-verify.js` so
any errors produced by that script were not failing the build.

PR-URL: nodejs#38983
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Makefile

@@ -350,7 +350,7 @@ test/addons/.docbuildstamp: $(DOCBUILDSTAMP_PREREQS) tools/doc/node_modules
 	else \
 		$(RM) -r test/addons/??_*/; \
 		[ -x $(NODE) ] && $(NODE) $< || node $< ; \
-		touch $@; \
+		[ $$? -eq 0 ] && touch $@; \
 	fi
 
 ADDONS_BINDING_GYPS := \