Currently the test default UI (for non-interactive tests like stressapptest) we can see the test parameters, but it's not evaluated yet. This is not convenient when debugging that we do want to quickly find out "what's the param in current stage", especially we have more eval-type params today in JSON test list.

I think we may want:
 - In goofy invocation, when the args were solved, make a copy to the invocation
 - test default UI should show both evaluated values AND original value (the eval string)
 - If possible, also provide a way so we can inspect params even if the test has its own UI, for example adding a button in additional to "mark failed", or a popup menu item.