test: set log_level to info in test-hwdb and check-help-*

These tests check the stderr. So, if the systemd.log_level=debug
is set in the kernel command line, then these tests fail.
This set log_level to info in hwdb-test.sh and meson-check-help.sh,
the kernel command line not to change the output of the target
programs.

Fixes #7362.

test/hwdb-test.sh

@@ -22,6 +22,7 @@
 
 set -e
 
+export SYSTEMD_LOG_LEVEL=info
 ROOTDIR=$(dirname $(dirname $(readlink -f $0)))
 SYSTEMD_HWDB=./systemd-hwdb
 

tools/meson-check-help.sh

@@ -1,5 +1,7 @@
 #!/bin/sh -eu
 
+export SYSTEMD_LOG_LEVEL=info
+
 # output width
 if "$1"  --help | grep -v 'default:' | grep -E -q '.{80}.'; then
         echo "$(basename "$1") --help output is too wide:"