Change equality test to reference comparison for mutable values

test/tests/equality operator.ans

@@ -1,19 +1,29 @@
-:a = [1=2]
+::a = [1=2]
 
-0 = {a == [5=2]}
+0 = {a == [5=2]!constant}
 
-0 = {a == [1=3]}
+0 = {a == [1=3]!constant}
 
-1 = {a == [1=2]}
+1 = {a == [1=2]!constant}
 
-:b = [1,2,3]
+::b = [1,2,3]
 
 0 = {b == a}
 
-0 = {b == []}
+0 = {b == []!constant}
 
-0 = {b == [3,1,2]}
+0 = {b == [3,1,2]!constant}
 
-0 = {b == [1,2,3,4]}
+0 = {b == [1,2,3,4]!constant}
 
-1 = {b == [1,2,3]}
+1 = {b == [1,2,3]!constant}
+
+:c = [1,2,3]
+
+0 = {c == b}
+
+1 = {c!constant == b}
+
+::d = [1,2,3]
+
+1 = {d == b}