Revert of Revert of Wrap runtime.js in a function.

src/symbol.js

Index: src/symbol.js
diff --git a/src/symbol.js b/src/symbol.js
index 72aa4d632416f0873db1637cd2a88f3482dd5a72..810501352817e1ad758e1c78b44fe4efff4ac0b4 100644
--- a/src/symbol.js
+++ b/src/symbol.js
@@ -26,7 +26,7 @@
 function SymbolConstructor(x) {
   if (%_IsConstructCall()) throw MakeTypeError(kNotConstructor, "Symbol");
   // NOTE: Passing in a Symbol value will throw on ToString().
-  return %CreateSymbol(IS_UNDEFINED(x) ? x : ToString(x));
+  return %CreateSymbol(IS_UNDEFINED(x) ? x : $toString(x));
 }
 
 
@@ -69,7 +69,7 @@
 
 // ES6 19.1.2.8
 function ObjectGetOwnPropertySymbols(obj) {
-  obj = ToObject(obj);
+  obj = $toObject(obj);
 
   // TODO(arv): Proxies use a shared trap for String and Symbol keys.