Expose SIMD.Float32x4 type to Javascript.

src/messages.h

Index: src/messages.h
diff --git a/src/messages.h b/src/messages.h
index 39127d5b5aa80bd153dc7cfe24aa50e52e390dda..a1d2d190359f3fd28eb5a2784b15b9b85684babf 100644
--- a/src/messages.h
+++ b/src/messages.h
@@ -242,6 +242,7 @@ class CallSite {
     "Cannot convert a Symbol wrapper object to a primitive value")             \
   T(SymbolToNumber, "Cannot convert a Symbol value to a number")               \
   T(SymbolToString, "Cannot convert a Symbol value to a string")               \
+  T(SimdToNumber, "Cannot convert a SIMD value to a number")                   \
   T(UndefinedOrNullToObject, "Cannot convert undefined or null to object")     \
   T(ValueAndAccessor,                                                          \
     "Invalid property.  A property cannot both have accessors and be "         \