Update V8 to r6387 as required by WebKit r76408

Change-Id: Icfc5385b0996bd592f8b1ac8cbb44767ee09f1f6
diff --git a/src/version.cc b/src/version.cc
index c1cc2fc..495de31 100644
--- a/src/version.cc
+++ b/src/version.cc
@@ -1,4 +1,4 @@
-// Copyright 2011 the V8 project authors. All rights reserved.
+// Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
@@ -34,7 +34,7 @@
 // cannot be changed without changing the SCons build script.
 #define MAJOR_VERSION     3
 #define MINOR_VERSION     0
-#define BUILD_NUMBER      7
+#define BUILD_NUMBER      9
 #define PATCH_LEVEL       0
 #define CANDIDATE_VERSION false