[intrinsic] Drop the %_ValueOf intrinsic.

src/js/messages.js

Index: src/js/messages.js
diff --git a/src/js/messages.js b/src/js/messages.js
index cd9c5e534ede1219bc5885d72a9ed06f32069bab..d01f3efdf4ac326327534e29b7346ca0fb9561f3 100644
--- a/src/js/messages.js
+++ b/src/js/messages.js
@@ -43,7 +43,6 @@ var ObjectToString = utils.ImportNow("object_to_string");
 var Script = utils.ImportNow("Script");
 var stackTraceSymbol = utils.ImportNow("stack_trace_symbol");
 var StringIndexOf;
-var SymbolToString;
 var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol");
 var Uint16x8ToString;
 var Uint32x4ToString;
@@ -60,7 +59,6 @@ utils.Import(function(from) {
   Int8x16ToString = from.Int8x16ToString;
   ObjectHasOwnProperty = from.ObjectHasOwnProperty;
   StringIndexOf = from.StringIndexOf;
-  SymbolToString = from.SymbolToString;
   Uint16x8ToString = from.Uint16x8ToString;
   Uint32x4ToString = from.Uint32x4ToString;
   Uint8x16ToString = from.Uint8x16ToString;
@@ -117,7 +115,7 @@ function NoSideEffectsToString(obj) {
     }
     return str;
   }
-  if (IS_SYMBOL(obj)) return %_Call(SymbolToString, obj);
+  if (IS_SYMBOL(obj)) return %SymbolDescriptiveString(obj);
   if (IS_SIMD_VALUE(obj)) {
     switch (typeof(obj)) {
       case 'float32x4': return %_Call(Float32x4ToString, obj);