build: use -9 with kill in Makefile

Fixes: #20194

PR-URL: #20195
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Makefile

@@ -393,7 +393,7 @@ clear-stalled:
 	ps awwx | grep Release/node | grep -v grep | cat
 	@PS_OUT=`ps awwx | grep Release/node | grep -v grep | awk '{print $$1}'`; \
 	if [ "$${PS_OUT}" ]; then \
-		echo $${PS_OUT} | xargs kill; \
+		echo $${PS_OUT} | xargs kill -9; \
 	fi
 
 .PHONY: test-gc
@@ -439,7 +439,7 @@ test-ci-js: | clear-stalled
 	ps awwx | grep Release/node | grep -v grep | cat
 	@PS_OUT=`ps awwx | grep Release/node | grep -v grep | awk '{print $$1}'`; \
 	if [ "$${PS_OUT}" ]; then \
-		echo $${PS_OUT} | xargs kill; exit 1; \
+		echo $${PS_OUT} | xargs kill -9; exit 1; \
 	fi
 
 .PHONY: test-ci
@@ -454,7 +454,7 @@ test-ci: | clear-stalled build-addons build-addons-napi doc-only
 	ps awwx | grep Release/node | grep -v grep | cat
 	@PS_OUT=`ps awwx | grep Release/node | grep -v grep | awk '{print $$1}'`; \
 	if [ "$${PS_OUT}" ]; then \
-		echo $${PS_OUT} | xargs kill; exit 1; \
+		echo $${PS_OUT} | xargs kill -9; exit 1; \
 	fi
 
 .PHONY: build-ci