Remote debug attach does not support path mapping

Following the directions here: https://docs.microsoft.com/en-us/visualstudio/python/debugging-python-code-on-remote-linux-machines?view=vs-2019

I cannot get breakpoints to bind.

Internally debugpy is returning this:

1> [DebugAdapter] <-- R (setBreakpoints-12) [20 ms]: {"type":"response","request_seq":12,"success":true,"command":"setBreakpoints","body":{"breakpoints":[{"verified":false,"message":"Breakpoint in file that does not exist.","source":{"path":"c:\\Users\\aku91\\source\\repos\\PythonApplication3\\PythonApplication3\\test.py","sources":[],"checksums":[]},"line":7}]},"seq":15}

This really means we need path mapping for the remote machine. There was some discussion in the past of VSCodeDebugAdapterHost supporting a launch.json that could provide that mapping. Short of that, we’d have to provide that here:

https://github.com/microsoft/PTVS/blob/984cd41766ea27a9b6ac304b437031e7d880899d/Python/Product/PythonTools/PythonTools/Debugger/DebugAdapter/DebugAdapterLauncher.cs#L167

We need to pass the attach request the path mappings like VS code does:

[int19h]

Since launch.vs.json would do more than just fix this issue, I think it would be best to track it separately - #7434

[int19h]

I doubt we’d be able to reuse the actual code, since C++ project system is very different from ours. But we can reuse their spec (i.e. where to look for the file and how to combine it with project settings), and to some extent probably the documentation.