Some functions in Process were using LLDB_INVALID_ADDRESS instead of
LLDB_INVALID_TOKEN.
The only visible effect of this appears to be that "process unload
<tab>" would complete to 0 even after the image was unloaded. Since the
command is checking for LLDB_INVALID_TOKEN.
Everything else worked somehow. I've added a check to the existing load
unload tests anyway.
The tab completion cannot be checked as is, but when I make them more
strict in a later patch it will be tested.