Don't use valgrind.

--- kbd-2.8.0/tests/valgrind.sh	2025-04-07 13:07:45.000000000 +0100
+++ kbd-2.8.0/tests/valgrind.sh	2025-05-30 13:44:03.494523549 +0100
@@ -3,6 +3,9 @@
 tool="$1"
 shift
 
+exec 1>stdout 2>stderr "$@"
+exit 1
+
 case "$tool" in
 	memcheck)
 		valgrind_args="--leak-check=full --leak-resolution=high --show-leak-kinds=all --track-origins=yes"