[strong] Implement static restrictions on switch statement

src/messages.js

Index: src/messages.js
diff --git a/src/messages.js b/src/messages.js
index 5900ed18e2a24cc3ecbf91f943de22f7bd1ba6ba..cc4912927ffe8792460c2a05172fa347a8fbf1d3 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -169,6 +169,7 @@ var kMessages = {
   strong_arguments:              ["In strong mode, 'arguments' is deprecated, use '...args' instead"],
   strong_undefined:              ["In strong mode, binding or assigning to 'undefined' is deprecated"],
   strong_direct_eval:            ["In strong mode, direct calls to eval are deprecated"],
+  strong_switch_fallthrough :    ["In strong mode, switch fall-through is deprecated, terminate each case with 'break', 'continue', 'return' or 'throw'"],
   strong_equal:                  ["In strong mode, '==' and '!=' are deprecated, use '===' and '!==' instead"],
   strong_delete:                 ["In strong mode, 'delete' is deprecated, use maps or sets instead"],
   strong_var:                    ["In strong mode, 'var' is deprecated, use 'let' or 'const' instead"],