upd readme

tracking/test_cases/q5/1-DiscreteDist-a1.test

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+class: "OutputTest"
+success: "PASS"
+failure: "NO PASS"
+
+# Python statements initializing variables for the test below.
+preamble: """
+import inference
+
+dist = inference.DiscreteDistribution()
+dist['a'] = 0
+ans5 = dist.normalize()
+
+# ans = map(float, [ans1, ans2, ans3, ans4])
+ans = map(float, [ans5 is None])
+"""
+
+# A python expression to be evaluated.  This expression must return the 
+# same result for the student and instructor's code.
+
+test: "ans"
+
+