Add ptvsd modules to DONT_TRACE

[int19h]

pydevd has a list of files that are excluded from tracing in pydevd_dont_trace_files.py. It's a dict, so we can add our own entries to it after loading that module.

[karthiknadig]

Is this part of Just my code?

[int19h]

It would probably have to be done as part of JMC, but it looks like it might have some minor perf benefits outside of that, even if we just add hardcoded list of our .py files there.

[karthiknadig]

@int19h Files in that list have pydevd_ prefix. We may need to put similar prefix ptvsd_ for that to work correctly, without out accidentally hiding users' files. What do you think?