WIP: new.target

src/messages.js

Index: src/messages.js
diff --git a/src/messages.js b/src/messages.js
index 04e107dfdc86482f9444a9f99d0ac37952e86a11..ed018c3a56c22033d2bec78197ed3156f83b7f11 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -154,6 +154,7 @@ var kMessages = {
   module_export_undefined:       ["Export '", "%0", "' is not defined in module"],
   duplicate_export:              ["Duplicate export of '", "%0", "'"],
   unexpected_super:              ["'super' keyword unexpected here"],
+  unexpected_new_target:         ["new.target expression is not allowed here"],
   extends_value_not_a_function:  ["Class extends value ", "%0", " is not a function or null"],
   prototype_parent_not_an_object: ["Class extends value does not have valid prototype property ", "%0"],
   duplicate_constructor:         ["A class may only have one constructor"],