Debugger does not format messages with path names correctly in cross platform scenarios.

There are a few instances where the debugger does not handle cross platform paths correctly. This can arise if an app is built on Windows and debugged on Linux/Mac (or vice versa). The paths coming from the pdb will not be the native path form of the machine (i.e. the pdb would contain Windows paths and the app is being debugged on linux). System.IO.Path apis such as GetFileName will fail to parse the windows paths because the API expects native paths.