tweewide: Fix most Shebang lines

Change every shebang which does not need an argument to use /usr/bin/env.
This is needed as not every distro has everything under /usr/bin,
sometimes not even bash.

Signed-off-by: Finn Behrens <me@kloenk.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/tools/testing/kunit/kunit.py b/tools/testing/kunit/kunit.py
index d4f7846..21516e2 100755
--- a/tools/testing/kunit/kunit.py
+++ b/tools/testing/kunit/kunit.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 #
 # A thin wrapper on top of the KUnit Kernel