Add a test case for Phi representations

test/mjsunit/compiler/phi-representations.js

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 // Flags: --allow-natives-syntax
 
-function boom() {
-  var a = {
-    foo: "bar",
-    foo: "baz"
+function ar() {
+  var r = undefined;
+  var f = 1;
+  while (f--) {
+    r = (typeof r === 'undefined') ? 0.1 : r;
   };
-  return a;
+  return (r - r);
 }
 
-assertEquals("baz", boom().foo);
-assertEquals("baz", boom().foo);
-%OptimizeFunctionOnNextCall(boom);
-assertEquals("baz", boom().foo);
+assertEquals(0, ar());
+assertEquals(0, ar());
+%OptimizeFunctionOnNextCall(ar);
+assertEquals(0, ar());
+
+function ar2() {
+  var r = undefined;
+  var f = 1;
+  while (f--) {
+    r = r === undefined ? 0.1 : r;
+  };
+  return (r - r);
+}
+
+assertEquals(0, ar2());
+assertEquals(0, ar2());
+%OptimizeFunctionOnNextCall(ar2);
+assertEquals(0, ar2());