Fix representation generalization for doubles.

test/mjsunit/regress/regress-347909.js

Index: test/mjsunit/regress/regress-347909.js
diff --git a/test/mjsunit/regress/regress-check-eliminate-loop-phis.js b/test/mjsunit/regress/regress-347909.js
similarity index 61%
copy from test/mjsunit/regress/regress-check-eliminate-loop-phis.js
copy to test/mjsunit/regress/regress-347909.js
index 3791c35f71ccfc50dd384978e449103b39f6bff7..90a8e6a759eab76afef1dc968c814bd9d324b147 100644
--- a/test/mjsunit/regress/regress-check-eliminate-loop-phis.js
+++ b/test/mjsunit/regress/regress-347909.js
@@ -4,18 +4,16 @@
 
 // Flags: --allow-natives-syntax
 
+var a = {y:1.5};
+a.y = 0;
+var b = a.y;
+a.y = {};
+var d = 1;
 function f() {
-  var o = {x:1};
-  var y = {y:2.5, x:0};
-  var result;
-  for (var i = 0; i < 2; i++) {
-    result = o.x + 3;
-    o = y;
-  }
-  return result;
+  d = 0;
+  return {y: b};
 }
-
 f();
 f();
 %OptimizeFunctionOnNextCall(f);
-assertEquals(3, f());
+f();