Correct setting of macOS taskpolicy variable

to the underlying exec-wrapper command.

Signed-off-by: Rod Chapman <rodchap@amazon.com>

Author: rod-chapman

scripts/tests

@@ -321,7 +321,7 @@ class Tests:
         if self.args.exec_wrapper is not None and self.args.exec_wrapper != "":
             res += self.args.exec_wrapper.split(" ")
         if self.args.mac_taskpolicy is not None:
-            res += ["taskpolicy", "-c", f"{mac_taskpolicy}"]
+            res += ["taskpolicy", "-c", f"{self.args.mac_taskpolicy}"]
 
         return res