- Process and store --cpu-prof-dir and --cpu-prof-name during
  Environment creation
- Start profilers in on `profiler::StartProfilers()`

Now the subclasses only need to override methods to

- Get the profile node from the profiler response message object
- Return the directory and file path

And the V8ProfilerConnection() would handle the rest of profile
serialization and message parsing. This makes it easier to
add other types of profiles in the future.