Debugger: Adapt expression eval users to async interface.

Factor out message constant for expression evaluation completion,
as multiple places will be using that.

ExpressionEvaluationWindow:
- Check for expression match immediately in listener hook, and
  don't bother dispatching to the message loop in such a case.
  Simplifies some of the other code.

InspectorWindow / WatchPromptWindow:
- Rather than attempting to evaluate an expression directly,
  we now defer to the async interface. Clean up and adjust accordingly.

TeamWindow:
- Adjust window creation calls due to parameter changes.

This leaves only the CLI dump memory command to be adapted.
packagefs: Package::Open(): Also log error code