tests/bios-tables: Improve portability by searching bash in the $PATH

Bash is not always installed as /bin/bash. In particular on OpenBSD,
the package installs it in /usr/local/bin.
Use the 'env' shebang to search bash in the $PATH.

Reviewed-by: Kamil Rytarowski <n54@gmx.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/tests/data/acpi/rebuild-expected-aml.sh b/tests/data/acpi/rebuild-expected-aml.sh
index bf9ba24..abdff70 100755
--- a/tests/data/acpi/rebuild-expected-aml.sh
+++ b/tests/data/acpi/rebuild-expected-aml.sh
@@ -1,4 +1,4 @@
-#! /bin/bash
+#!/usr/bin/env bash
 
 #
 # Rebuild expected AML files for acpi unit-test