Make Error.prototype.toString spec compliant; and fix various side-effect-free error printing metho…

src/execution.h

Index: src/execution.h
diff --git a/src/execution.h b/src/execution.h
index 8b4056bc7d430164e7cd34c216ed80e791ee0f35..afbd1da45b2c2854c42cbe724671a772e1441f21 100644
--- a/src/execution.h
+++ b/src/execution.h
@@ -52,10 +52,6 @@ class Execution final : public AllStatic {
                                      Handle<Object> argv[],
                                      MaybeHandle<Object>* exception_out = NULL);
 
-  // ECMA-262 9.8
-  MUST_USE_RESULT static MaybeHandle<Object> ToDetailString(
-      Isolate* isolate, Handle<Object> obj);
-
   // ECMA-262 9.9
   MUST_USE_RESULT static MaybeHandle<Object> ToObject(
       Isolate* isolate, Handle<Object> obj);