use "/usr/bin/env python" in test_run_cmd_script

Author: branfosj

test/framework/run.py

@@ -543,7 +543,7 @@ def test_run_cmd_script(self):
         """Testing use of run_cmd with shell=False to call external scripts"""
         py_test_script = os.path.join(self.test_prefix, 'test.py')
         write_file(py_test_script, '\n'.join([
-            '#!/usr/bin/python',
+            '#!/usr/bin/env python',
             'print("hello")',
         ]))
         adjust_permissions(py_test_script, stat.S_IXUSR)