Remove bashisms from tests.

Those tests don't actually need bash. Just use common shebang.

tests/grub_cmd_date.in

@@ -1,4 +1,4 @@
-#! /bin/bash
+#! @BUILD_SHEBANG@
 set -e
 
 . "@builddir@/grub-core/modinfo.sh"

tests/grub_cmd_regexp.in

@@ -1,4 +1,4 @@
-#! /bin/bash
+#! @BUILD_SHEBANG@
 set -e
 
 # Run GRUB script in a Qemu instance

tests/grub_cmd_set_date.in

@@ -1,4 +1,4 @@
-#! /bin/bash
+#! @BUILD_SHEBANG@
 set -e
 
 . "@builddir@/grub-core/modinfo.sh"

tests/grub_cmd_sleep.in

@@ -1,4 +1,4 @@
-#! /bin/bash
+#! @BUILD_SHEBANG@
 set -e
 
 . "@builddir@/grub-core/modinfo.sh"

tests/grub_cmd_test.in

@@ -1,4 +1,4 @@
-#! /bin/bash
+#! @BUILD_SHEBANG@
 
 # create a randome file
 empty="`mktemp "${TMPDIR:-/tmp}/tmp.XXXXXXXXXX"`" || exit 1

tests/grub_cmd_tr.in

@@ -1,4 +1,4 @@
-#! /bin/bash -e
+#! @BUILD_SHEBANG@ -e
 
 # Run GRUB script in a Qemu instance
 # Copyright (C) 2010  Free Software Foundation, Inc.

tests/grub_func_test.in

@@ -1,4 +1,4 @@
-#! /bin/bash
+#! @BUILD_SHEBANG@
 set -e
 
 . "@builddir@/grub-core/modinfo.sh"

tests/grub_script_blockarg.in

@@ -1,4 +1,4 @@
-#! /bin/bash
+#! @BUILD_SHEBANG@
 
 # Run GRUB script in a Qemu instance
 # Copyright (C) 2010  Free Software Foundation, Inc.

tests/grub_script_expansion.in

@@ -1,4 +1,4 @@
-#! /bin/bash
+#! @BUILD_SHEBANG@
 set -e
 
 # Run GRUB script in a Qemu instance

tests/help_test.in

@@ -1,4 +1,4 @@
-#! /bin/bash
+#! @BUILD_SHEBANG@
 set -e
 
 . "@builddir@/grub-core/modinfo.sh"

tests/test_sha512sum.in

@@ -1,4 +1,4 @@
-#! /bin/bash
+#! @BUILD_SHEBANG@
 
 # create a randome file
 file="`mktemp "${TMPDIR:-/tmp}/tmp.XXXXXXXXXX"`" || exit 1