Implement handling of arrow functions in the parser

src/messages.js

Index: src/messages.js
diff --git a/src/messages.js b/src/messages.js
index fd94cc0ede9ed26c49f96e1171c9273d2b98545a..c841bcbd8b31514e3b98826e988b76e9ca9533cd 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -156,6 +156,7 @@ var kMessages = {
   strict_cannot_assign:          ["Cannot assign to read only '", "%0", "' in strict mode"],
   strict_poison_pill:            ["'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them"],
   strict_caller:                 ["Illegal access to a strict mode caller function."],
+  strict_parameter_list:         ["Malformed strict mode parameter list"],

[marja, 2014/06/26 14:38:13]

This error message is not about strict mode parameter lists, so you should call
it "malformed_arrow_function_parameter_list" and the message should be
"Malformed arrow function parameter list".

   generator_poison_pill:         ["'caller' and 'arguments' properties may not be accessed on generator functions."],
   unprotected_let:               ["Illegal let declaration in unprotected statement context."],
   unprotected_const:             ["Illegal const declaration in unprotected statement context."],