Prettify output

[PiotrSikora]

The current output is a bit rough and while fine for debugging, it's not very readable output that you want to see when running tests.

Consider using something like this:

• [vm->host] function(params...) for host call entry,
• [vm<-host] function return: X for host call return,
• [host->vm] function(params...) for callback entry,
• [host<-vm] function return: X for callback return.

with either OK, FAILED, UNEXPECTED being printed out on the right hand side, depending on the expectations.

[PiotrSikora]

cc @agiachris

[agiachris]

should params include the names and also the assigned values?
e.g. [host->vm] proxy_on_vm_start(root_context_id=1, parent_context_id=0)
or something like: [host->vm] proxy_on_vm_start(root_context_id, parent_context_id)

[PiotrSikora]

Please include values.