Implement new Function.prototype.toString and fix CreateDynamicFunction parsing

src/parsing/preparser.h

Index: src/parsing/preparser.h
diff --git a/src/parsing/preparser.h b/src/parsing/preparser.h
index 9291578dbce579f580b9b1004ac7b56d4856a125..f522471532a0527a392537b252774dfb62f8c44c 100644
--- a/src/parsing/preparser.h
+++ b/src/parsing/preparser.h
@@ -1671,6 +1671,8 @@ class PreParser : public ParserBase<PreParser> {
     if (use_counts_ != nullptr) ++use_counts_[feature];
   }
 
+  V8_INLINE bool ParsingDynamicFunctionDeclaration() const { return false; }
+
   // Preparser's private field members.
 
   int* use_counts_;