Revert of Migrate error messages, part 2.

src/generator.js

Index: src/generator.js
diff --git a/src/generator.js b/src/generator.js
index 484afd8d6a51f62292ed178c3c5973c53d1dc134..031d56e37e3612bdb98f0a3822e24c500093f427 100644
--- a/src/generator.js
+++ b/src/generator.js
@@ -16,8 +16,8 @@
 
 function GeneratorObjectNext(value) {
   if (!IS_GENERATOR(this)) {
-    throw MakeTypeError(kIncompatibleMethodReceiver,
-                        '[Generator].prototype.next', this);
+    throw MakeTypeError('incompatible_method_receiver',
+                        ['[Generator].prototype.next', this]);
   }
 
   var continuation = %GeneratorGetContinuation(this);
@@ -35,14 +35,14 @@
     return { value: void 0, done: true };
   } else {
     // Generator is running.
-    throw MakeTypeError(kGeneratorRunning);
+    throw MakeTypeError('generator_running', []);
   }
 }
 
 function GeneratorObjectThrow(exn) {
   if (!IS_GENERATOR(this)) {
-    throw MakeTypeError(kIncompatibleMethodReceiver,
-                        '[Generator].prototype.throw', this);
+    throw MakeTypeError('incompatible_method_receiver',
+                        ['[Generator].prototype.throw', this]);
   }
 
   var continuation = %GeneratorGetContinuation(this);
@@ -59,7 +59,7 @@
     throw exn;
   } else {
     // Generator is running.
-    throw MakeTypeError(kGeneratorRunning);
+    throw MakeTypeError('generator_running', []);
   }
 }