Add SIMD.Float32x4 functions.

test/mjsunit/messages.js

Index: test/mjsunit/messages.js
diff --git a/test/mjsunit/messages.js b/test/mjsunit/messages.js
index 8dce6f0ab332cda1e0c3b895ed5f4b5a1f382193..7962b9e0b56557729bd40302131da02b8ae0c7be 100644
--- a/test/mjsunit/messages.js
+++ b/test/mjsunit/messages.js
@@ -323,6 +323,11 @@ test(function() {
   1 + Symbol();
 }, "Cannot convert a Symbol value to a number", TypeError);
 
+// kSimdToNumber
+test(function() {
+  1 + SIMD.Float32x4(1, 2, 3, 4);
+}, "Cannot convert a Simd value to a number", TypeError);
+
 // kUndefinedOrNullToObject
 test(function() {
   Array.prototype.toString.call(null);