Fix spread/rest emit for symbols.

It used the index of the symbol property as the name, not the symbol
itself.

Author: sandersn

src/compiler/emitter.ts

@@ -39,8 +39,8 @@ var __assign = (this && this.__assign) || Object.assign || function(t) {
         for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
             t[p] = s[p];
         if (typeof Object.getOwnPropertySymbols === "function")
-            for (var i = 0, s = Object.getOwnPropertySymbols(s); i < s.length; i++)
-                t[i] = s[i];
+            for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++)
+                t[p[i]] = s[p[i]];
     }
     return t;
 };`;
@@ -51,8 +51,8 @@ var __rest = (this && this.__rest) || function (s, e) {
     for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)
         t[p] = s[p];
     if (typeof Object.getOwnPropertySymbols === "function")
-        for (var i = 0, s = Object.getOwnPropertySymbols(s); i < s.length; i++) if (e.indexOf(s[i]) > 0)
-            t[i] = s[i];
+        for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)
+            t[p[i]] = s[p[i]];
     return t;
 };`;