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.
Shell scripts should be executable so that meson reports their
invocation succinctly (does not print 'sh' '-e').
Python scripts should not be executable so that meson does the
detection of the right python binary itself.
Add -u everywhere to catch potential errors.
bleep_blop