[parser] early error when declaration Pattern missing Initializer

src/messages.h

Index: src/messages.h
diff --git a/src/messages.h b/src/messages.h
index 83413e8be71590dfa3622bb9cc36c9172411cd60..46310d804f561a3270f44b61800e9c0d3880f156 100644
--- a/src/messages.h
+++ b/src/messages.h
@@ -127,6 +127,8 @@ class CallSite {
   T(InstanceofNonobjectProto,                                                  \
     "Function has non-object prototype '%' in instanceof check")               \
   T(InvalidArgument, "invalid_argument")                                       \
+  T(InvalidDestructuringDeclaration,                                           \

[adamk, 2015/11/03 20:13:53]

Looks like we're currently giving bad error messages for this for the const
case, so it seems like this could just be "MissingInitializer" and the message
could be broadened to cover that case too.

+    "Missing initializer in destructuring declaration")                        \
   T(InvalidInOperatorUse, "Cannot use 'in' operator to search for '%' in %")   \
   T(IteratorResultNotAnObject, "Iterator result % is not an object")           \
   T(IteratorValueNotAnObject, "Iterator value % is not an entry object")       \