Bug 499019: don't report errors for code that is 'not reached', even as an intermediate result, r=jorendorff

js/src/jsstack.js

@@ -172,7 +172,8 @@ RedGreenCheck.prototype.flowState = function(isn, state) {
   //  warning("(Remove the workaround in jsstack.js and recompile to get a JS stack trace.)",
   //          location_of(isn));
   //}
-  let green = (state.get(this._state_var_decl) != 1);
+  let stackState = state.get(this._state_var_decl);
+  let green = stackState != 1 && stackState != ESP.NOT_REACHED;
   let redInfo = isn.redInfo;
   if (green && redInfo) {
     error(redInfo[0], redInfo[1]);