Update V8 to r6387 as required by WebKit r76408

Change-Id: Icfc5385b0996bd592f8b1ac8cbb44767ee09f1f6
diff --git a/src/preparser.h b/src/preparser.h
index 536e6d4..66fad3b 100644
--- a/src/preparser.h
+++ b/src/preparser.h
@@ -144,7 +144,8 @@
         scope_(NULL),
         stack_limit_(stack_limit),
         stack_overflow_(false),
-        allow_lazy_(true) { }
+        allow_lazy_(true),
+        parenthesized_function_(false) { }
 
   // Preparse the program. Only called in PreParseProgram after creating
   // the instance.
@@ -268,6 +269,7 @@
   uintptr_t stack_limit_;
   bool stack_overflow_;
   bool allow_lazy_;
+  bool parenthesized_function_;
 };
 } }  // v8::preparser