fix bugs with getter/setter (#1926)

- `reduce_vars`
- `side_effects`
- property access for object
- `AST_SymbolAccessor` as key names

enhance `test/ufuzz.js`
- add object getter & setter
  - property assignment to setter
  - avoid infinite recursion in setter
- fix & adjust assignment operators
  - 50% `=`
  - 25% `+=`
  - 2.5% each for the rest
- avoid "Invalid array length"
- fix `console.log()`
  - bypass getter
  - curb recursive reference
- deprecate `-E`, always report runtime errors

test/sandbox.js

@@ -1,14 +1,16 @@
 var vm = require("vm");
 
-function safe_log(arg) {
+function safe_log(arg, level) {
     if (arg) switch (typeof arg) {
       case "function":
         return arg.toString();
       case "object":
         if (/Error$/.test(arg.name)) return arg.toString();
         arg.constructor.toString();
-        for (var key in arg) {
-            arg[key] = safe_log(arg[key]);
+        if (level--) for (var key in arg) {
+            if (!Object.getOwnPropertyDescriptor(arg, key).get) {
+                arg[key] = safe_log(arg[key], level);
+            }
         }
     }
     return arg;
@@ -48,7 +50,9 @@ exports.run_code = function(code) {
         ].join("\n"), {
             console: {
                 log: function() {
-                    return console.log.apply(console, [].map.call(arguments, safe_log));
+                    return console.log.apply(console, [].map.call(arguments, function(arg) {
+                        return safe_log(arg, 3);
+                    }));
                 }
             }
         }, { timeout: 5000 });