tests/module: nix-ify

Use "#!/usr/bin/env bash" instead of "#!/bin/bash". This is necessary
for nix environments as they only provide /usr/bin/env at the standard
location.

Signed-off-by: Joel Granados <joel.granados@kernel.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20250122-jag-nix-ify-v1-1-addb3170f93c@kernel.org
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>

lib/tests/module/gen_test_kallsyms.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 TARGET=$(basename $1)
 DIR=lib/tests/module