[ic][mips][mips64] Ensure store handlers return value in proper register.

test/mjsunit/regress/regress-crbug-650973.js

Index: test/mjsunit/regress/regress-crbug-650973.js
diff --git a/test/mjsunit/regress/regress-crbug-577112.js b/test/mjsunit/regress/regress-crbug-650973.js
similarity index 58%
copy from test/mjsunit/regress/regress-crbug-577112.js
copy to test/mjsunit/regress/regress-crbug-650973.js
index 504f921a335801a51fd1c0c1a39a8b08e8872722..9c2d8c67475656c150fb3f79aeac3e27afd35a1d 100644
--- a/test/mjsunit/regress/regress-crbug-577112.js
+++ b/test/mjsunit/regress/regress-crbug-650973.js
@@ -4,12 +4,15 @@
 
 // Flags: --allow-natives-syntax
 
-Array.prototype.__proto__ = null;
-var prototype = Array.prototype;
+var v = {p:0};
+// Turn the object into dictionary mode.
+v.__defineGetter__("p", function() { return 13; });
+
 function f() {
-  prototype.lastIndexOf({});
+  var boom = (v.foo = v);
+  assertEquals(v, boom.foo);
 }
+
 f();
 f();
-%OptimizeFunctionOnNextCall(f);
 f();