Promises: some adaptations to spec

src/messages.js

Index: src/messages.js
diff --git a/src/messages.js b/src/messages.js
index c7096724ace127053e80327f116de8c3d34ac646..225e83f530d47b2e339bd4876ffbf666b62d7405 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -109,8 +109,8 @@ var kMessages = {
   invalid_argument:              ["invalid_argument"],
   data_view_not_array_buffer:    ["First argument to DataView constructor must be an ArrayBuffer"],
   constructor_not_function:      ["Constructor ", "%0", " requires 'new'"],
-  not_a_promise:                 ["%0", "is not a promise"],
-  promise_cyclic:                ["Chaining cycle detected for promise", "%0"],
+  not_a_promise:                 ["%0", " is not a promise"],
+  promise_cyclic:                ["Chaining cycle detected for promise ", "%0"],
   array_functions_on_frozen:     ["Cannot modify frozen array elements"],
   array_functions_change_sealed: ["Cannot add/remove sealed array elements"],
   // RangeError