Revert "removing copy-back-to-sandbox in vm"

After a long discussion with @isaacs, we’ve decided to defer consideration of
API changes to ~0.7, and reduce this change to a relatively safe subset of
changes that don’t affect the API for immediate inclusion in 0.6.

The changes reverted in this commit will be coming back in 0.7, after a
discussion of the alternatives.

This reverts commit 2c1f5206bbb23bd34624acbcfb475dddcda0b883.

src/node_script.cc

@@ -439,6 +439,11 @@ Handle<Value> WrappedScript::EvalMachine(const Arguments& args) {
     result = args.This();
   }
 
+  if (context_flag == userContext || context_flag == newContext) {
+    // success! copy changes back onto the sandbox object.
+    CloneObject(args.This(), context->Global()->GetPrototype(), sandbox);
+  }
+
   if (context_flag == newContext) {
     // Clean up, clean up, everybody everywhere!
     context->Exit();

test/simple/test-script-context.js

@@ -40,7 +40,7 @@ assert.equal('lala', context.thing);
 common.debug('test updating context');
 script = new Script('foo = 3;');
 result = script.runInContext(context);
-//assert.equal(3, context.foo); // TODO: REIMPLEMENT ME
+assert.equal(3, context.foo);
 assert.equal('lala', context.thing);
 
 // Issue GH-1801

test/simple/test-script-new.js

@@ -69,8 +69,8 @@ foo = 2;
 sandbox = { foo: 0, baz: 3 };
 script = new Script(code);
 var baz = script.runInNewContext(sandbox);
-//assert.equal(1, context.foo); // TODO: REIMPLEMENT ME
-//assert.equal(2, context.bar); // TODO: REIMPLEMENT ME
+assert.equal(1, sandbox.foo);
+assert.equal(2, sandbox.bar);
 assert.equal(2, foo);
 
 common.debug('call a function by reference');