Improve error handling when things fail on the command line

[Praburaj]

[On Helios]:
[On CoreCLR]:
Starting yesterday's build, I'm seeing that any compilation error in a C# file (say Startup.cs) is not being displayed on the command line. The Helios error page simply displays a FileLoadException Application.dll

[On DesktopCLR]:
No compilation errors being printed on command line, but the Helios error page shows the compilation errors

[Selfhost]: klr.exe crashes when application has a compilation error. Apart from that I see the same problem with respect to compilation errors listed.
[OnCoreCLR]: The compilation errors are swallowed and I can only see klr.exe crashing with a FileNotFound exception on application.dll
[DesktopClr]: The compilation errors are listed and klr.exe crashes.

Expectation:

1. Compilation errors bubbled up in CoreClr.
2. klr.exe should not crash instead just show the compilation errors and gracefully stop.

[davidfowl]

The bug in core clr was fixed (bug on their end). The k bubbling the exception is new. We can handle that in the right layer.

[Praburaj]

This fix should also address the case when k.cmd is being run on a folder without project.json it should exit gracefully without the error message we print now.

[davidfowl]

Updated the title